Equally on par in what sense? Since you don't interact with the 1v1 debating arena, I assume you mean the forum part of the website. There's all sorts, through from big bad Reddit itself (as well as Quora) to DebateIsland to basically any forum on any niche topic you want. What makes this website unique (now the DDO is dead) is its dedication to the wide array of debate topics and the 1v1 arena.
Honestly, if you ask me, the issue is that debating is an extremely niche passion that barely anyone in this generation is into. Most people see arguing as bad social skills and see debating as a pseudohobby that only argumentative pricks take. You prove them right on that and in some ways we all do. People generally prefer to seek out people that agree with them, those of us wired to seek out disagreement and enjoy it are often too dumb or ruthless to maintain it as a healthy hobby.
That was what made DDO unique and what makes this website unique enough, if the voting department was more active and better moderated.
If the 1v1 arena was actually popular and not a silly niche that barely anybody on the website uses and this website somewhere that barely anyone on the Internet uses, we'd see a healthier environment but outlying opinions and very harsh pushers of offensive opinion like yourself would be shunned to the outskirts.
So, the optimal population would be in the hundreds, not the thousands, in my opinion. We'd want around 250 dedicated, regular posters.