Believe me, I get what you mean. I'm so fuc**** tired of the way authors portray BL relationships with the HEAVY toxicity and abusive behavior, and then trying to tell us that's love. That's why, even if I've been reading for more than 10 years now, I can count the stories I actually like with one hand. And Banana Scandal is in second place, if not in the first one. And this is because of the respectful way author treats the characters, the story and mainly, the heavy themes. 

Taehwan, the ML, has a very toxic behavior mostly the whole season 2, I won't deny that. And Yeonwuu, the MC, also has a passive attitude, as you said. But what I think is different here is that from the very beginning, Taehwan knows very well that the way he acts is not correct, and he even asks himself why Yeonwuu accepts all his sh**. Of course, his set of mind uses that to go against Yeonwu even more at first. 

And about Yeonwu, he's never displayed as the classic "victim" character in BL relationships. Just like Taehwan, he's in his own bubble. He accepts sh*** from everyone and uses everyone (even Taehwan) because he's a victim, yes, but a victim of himself. He'll accept whatever Taehwan gives him because he can't let him go. And, unlike other stories, author always subtly lets you know that both of them are so wrong, that there are lots of things that aren't working. That the story is not "yay, here you have two toxic boyfriends that fu** a lot🖤" kind. Both are victims and victimizers in a way and the whole paths they walk to find themselves before finding each other is one of the most beautiful, painful, realistic and, again, respectful, I've read in a BL. 

That's why I'll say that I respect your opinion, but if you dropped it, also I'll recommend you give it another chance and pay attention to the things I've said about the thoughts of the characters and the way the story is told.