Thanks for the deeper discussion about this subject, I rarely have these and this is a subject I care a lot for and like to discuss. I'm going to get into a lot more details because of that.

The base for speedrunning is that you get a game in your hands and being told to "Reach the end/Beat the game". That's the only goal, the only definition. What do you expect you are allowed and not to do? A lot of people will have their own rules for this. "You have to enjoy the story", "You have to kill this boss", "You have to do this mini game", "You have to beat all levels", "You have to get a 100% collection rate" and so on. Everyone will play through the game differently, there are no consistent rules that you go by. For speedrunning this used to be a problem, where lots of different opinions on what you have to do for it to count. Both counting glitches and things that may seem like glitches but really aren't. Then also what kind of glitches they are, as glitches in general were commonly already allowed. But which glitch should be allowed and which should be banned?

This is pretty much where the "any%" category came to be. The name originated from Metroid Prime, where the game will award you depending on the amount of items you collected. There was "100%", simply collecting all items and then the community named it "any%", where you could get as many items as you wanted, with the pure goal of beating the game quickly. This "Beat the game" category later became the standard definition where you were simply allowed to use what the game has to offer to accomplish your goal, outside of in-game cheat codes. This makes the rules for every game very simple, there's nothing to discuss. Which would previously take a very long time where the community talks about every kind of glitch and not if it should be allowed. It was tedious, caused a lot of drama and anger.

Of course, many games have more than one category. "Any%" doesn't have to be the biggest one. For a game like A Link to the Past it's a short and pretty boring run to both watch and do. But the category isn't made to be more fun than something else, it's not made to show who is the most skilled person in the game. The now-called "No major glitches" category has become the standard one for ALttP. It shows off more of the game, you can put your skills to the test and is overall more interesting.

But here's the problem: What is a major glitch? What is a glitch at all? How can we easily determine these things? The truth is: we can't. Sure, let's just call Shigeru Miyamoto and ask about every single thing in the game. At many times, developers do however support the use of glitches in their games. Miyamoto has claimed on several occasions that many glitches are "more like features" and that they were left in the game on purpose because of this. Such examples being the - World in Super Mario Bros. and Ocarina of Time 3D. In Nintendo's official strategy guide for Super Mario Bros. 3, they even show some glitches; Walljumping, enter a door in midair. That would clearly mean they are supposed to be used, or simply because they aren't glitches at all. How can we tell the difference? As soon as you start banning glitches, exploits, tricks etc. the rules will get arbitary. The rules are decided by the community of players who either run the game or are very familiar with the game. And try to make the rules as logical as possible. And the community deciding the rules is the same thing as any kind of chief judges for a sport or some other kind of tournament. What they decide the rules are, the rest of us simply have to follow. It's no different for speedrunning, except here we decide it as a community through discussions. Instead of having it as one main judge who makes all the calls and can practically ignore what the players think. We create the rules for ourselves, for them to be logical and for us to have fun while running.

Other developers have showed their support to glitches because they extend their game world, it gives the player new ways to explore and play the game. The developer has created a world they want the player to have fun with, to come back to and still enjoy. Glitches will allow that. And if they do find a game that doesn't harm the game, such as crashing it, making it unbeatable etc. why should they waste time and money to fix it? Those who enjoy them can try to explore the game deeply to discover them, those who don't enjoy them can simply ignore it. For Nintendo World Championships, speedrunners who were known for their heavy glich runs, were invited to take part of the contest. The commentators also opened talked about glitches during the competition. There were no rules for glitches. You only had a set goal "Beat this" and everything within your power to do, within the game's boundaries, you were allowed to take advantage over. For other video game competitions and e-sport, there are games were  certain glitches are indeed allowed. Again, it all depends on the rules set for it. Breaking the rules is cheating. If glitches are banned, then you are cheating and thus will be disqualified. This makes perfect sense.

We've had game developers on commentary during speedrun marathons, such as Games Done Quick and European Speedster Assembly. They are curious to see what the runners are able to do with their game, what kind of things that have been found that they didn't know about. Which they have found very entertaining to watch. If I made a game, and someone found a "credits warp" glitch, would I be mad? Most likely not. That player had most likely played through the game before, probably many times. And I created the game for people to enjoy. If he enjoys playing it like that, then I have succeeded with my task. Those who like to play it like that may do so, and those who don't have the option to play it in a different method. I don't decide how people should play a game, I create the world, give them a character and a set of basic moves they can use. How they use these moves in the world, that's up for the player to decide, not me.

As of your example with the painting... The same thing about games: The creator of the game make the world for people to enjoy the world in their own way. If I make a painting, people can enjoy it the way they like as well. I would be highly interested to hear what people would say, what kind of weird things they might come up with. It's showcasing imagination, I support that. Sure, if the picture draw a lot of negative attention to it, maybe I wouldn't be happy about it. But that is kinda expected. Some will come up with such theories simply to try "bring me down", to make stories, to have the papers write something about it. The same way some players might enjoy your game. I would feel sad as well, as I spent a lot of time with it. But that is to be expected. Everyone won't enjoy the game, everyone won't play it the way I "intended" and everyone won't like my painting or look at it the way I imagined when it was made.

I hope I managed to make some of my points more clearer =). I could go into more depth if you want me too. Like I didn't really explain how and why we determine what is a glitch and not, for glitchless rules. But that will be for another post...