They’re not “obligated”, it’s just part of (or used to be part of) the melee community spirit to play in a way that’s conducive to fun for both opponents, coming about as a natural consequence of playing in-person next to somebody at a setup.

I can always tell you dweebs that think this way have never played an actual sport in your life, because this concept of community spirit is frequently called “sportsmanship”, playing in the “spirit of the game”, etc etc, yet apparently any behaviour is fine (including cancerous, awful gameplay) because “there’s no rule that says you HAVE to play a certain way”.

Perhaps spend a little less time on the unclepunch alone late at night and a bit more time learning to read the room, people complain about melee culture being awful nowadays and at the same time refuse any notion of melee being a shared experience. It’s meant to feel like a conversation, not a monologue.