Taking the same tactic as Oak, let's look at the list of definitely on-topic things from the help center:
- Gameplay strategies and tactics
- Puzzle solving or obstacle clearing
- Game mechanics and terminology
- Plot and characters in games
- Game-specific hardware and utilities
It's not clear that questions about esports tournaments would fall under any of these categories. That being said, this is not an exhaustive list. The lead up to the list is "If your question generally covers things such as". So this is just a list of the kind of things we want to cover.
Now, let's consider the list of definitely off-topic things:
- Game and Mod Development (try the Game Development Stack Exchange instead)
- Speculative questions about developer intent, with respect to both mechanics and narrative
- Requests for game identification based on personal recollection alone
- Catalogues (listing games that fit specific criteria or are like an existing game)
- Shopping advice and recommendations
- Speculation of the future of the industry and of upcoming releases
- Piracy, and support with pirated games.
A question about esports tournaments is definitely not any of those things.
So, should it be on-topic?
Yeah, I think so.
It's a closely-related thing that gamers would tend to know about, even if it's not strictly part of the game. This seems as game-related as game hardware or terminology. We let people ask about those because they are required to play the game, or at least make playing the game easier. If you are playing an esports game, then understanding the tournament structure definitely helps.