Why is Victor bottom

It's a fandom. Victor is kinda seen as a seke (can go either way, top or bottom) So there are seperate Yuuri X Victor and Victor X Yuuri (more popular) fandoms. Just like there's Ereri and Riren fandoms.

ngl, I do myself prefer Viktor is top, but what can you do? It's actually pretty cute to see them like this, from what I can see, Viktor is pure bean and Yuuri is le dominant one with experience (if you know what I mean). Switched roles is expected in some doujinshis(?) idek how to spell.