I was wondering about the meaning of 「(なら)まだしも」: I can't find it in my grammar books, but I found (here, here and others) that it means "... would be acceptable; ... would be better", followed by something which isn't acceptable/is worse, like 「一度ならまだしもここまで六回その言葉を間違えって書いた」 (from here).
My doubt is: can it, given the right wording, mean the opposite, like 「XならまだしもB」, "X wouldn't be acceptable, but I don't see the issue with B"? My doubt comes from this, from a story I'm having a lot of difficulties understanding (and this is the first time I saw this grammar construction); context: a boy was seen peeing outside school, and the protagonist takes responsability, despite not being guilty, because the search for the culprit was blocking classes and lunch break; his grandmother is speaking with the principal and viceprincipal:
I don't really understand the central part, from 「大の男」 to 「てえの」, but I'm guessing 「見附」 means something like "in front across the street" (Weblio, meaning 3); I have no clue about 「十文字」, but I think 「てえの」 is dialectal for 「というの」, so I guess it means something like "an adult men showing his testicles (金玉) and urinating across the street".
I could take 「ならまだしも」 to mean "X is acceptable, but B isn't", so that would mean (I think) that a woman showing her butt in public would be (somehow) acceptable, but a man showing is testicles and urinating isn't; but 「いったいどこか都合悪い」 seems to me to mean "where the hell is the problem?".
So, my general understanding of the sentences is something like "A woman showing her butt in public would be one thing, but where the hell is the problem in a man showing his testicles and urinating across the street?". But this would reverse the meaning of 「ならまだしも」, and while the sentence does make sense in English (meaning-wise) I'm not really sure that what's the character is saying.