Obviously, you're entitled to your own opinion, but if you're going to raise a debate for breaking the concept of genre classification...I'd like to see a stronger argument than it "has it's own tropes".
Genres are supposed to be the broad umbrellas in which we group things of similar subject matter. Sub genres composed the breadth of styles/forms that rest underneath.
In a world/system where steampunk, alien invasion, time travel and cyberpunk are still firmly filed under Science Fiction you're gonna have to make a hellava argument to explain how BL has escaped the gravitational pull of Romance.
I doubt even the paper pushers at Tapas believe that BL has reached a point it's so distinguishable artistically from Romance that it defied traditional categorization. They made a BUSINESS decision...and we're seeing the progression from that business decision.