Why the fuck does every board use /v/ as their personal toilet? You see memes from /a/, /tv/, /int/, /pol/, /r9k/, yet all these boards claim to hate /v/ with a passion (despite the fact that they're greatly contributing towards its shittiness).
Begging the Question. "Does every board use /v/ as their personal toilet?" The answer is no. Assuming the answer to that question was yes, we can try to find the reason why it would be. "Because" can take many forms. I'll outline the four most common meanings why something might be.
Motivation: Other boards use /v/ as their personal toilet because they have an overlap in interests. /v/ appeals to more people than other hobbies. Video Games are enjoyed by many people whereas those other boards you've listed (with the exception of /tv/) are quite niche. When they come to /v/ they bring their own memes. The reason they hate /v/ is because of just that. The board is so large that they are forced to share it with the other niche hobbyists whom they disagree with a lot. Both /pol/ and /a/ like to play video games, but /pol/ and /a/ hate each other.
Justification: "I like video games, so I can post on /v/. I will just be myself because being myself has never harmed me elsewhere."
Logical Entailment: Every board uses /v/ as their personal toilet, ergo, every board uses /v/ as their personal toilet.
Physical cause and effect: Human beings interface with devices known as computers, connected to each other over a protocol called HTTP to display information on many glowing rectangles.
I feel that /co/ is like that to a lesser extent. Every now and then there are threads on things like the Star Wars films and Undertale. The Toonami threads are the most blatant example as they're only allowed because the denizens of /a/ rejected them that much.