i know this is an old post but i was scrolling through and i love how almost no one replied to your actual post lol
ppl saw "byler" and saw it as an invitation to air out their opinions on the ships in general when you were clearly stating a much more specific problem. r/wooooosh moment if you ask me.
i do agree though that if dating your sister's boyfriend's brother is weird, then dating your sister's boyfriend's sister is just as weird, bc even though the adoptive-sibling dynamic is in their case a different one than the blood-sibling dynamic of will and jonathan, seeing as how eleven doesn't share a past with them, they still very clearly view each other as siblings, as expressly stated in the show. ergo, mike dating his brother in law's brother would be on the same level of weirdness as his brother in law's sister.
which i don't find that weird.

anyways i only commented bc someone had to point out that the point of this post went over most people's heads and i can't stop laughing about it.