To me the chapter just reads like standard anime/manga fare, not in any sort of bad way. "Teen boys are always horny!" - that's why you got all the constant crap like panty stealing and sniffing and peeping and whatnot and the excuse is always "boys will be boys". Heck, there's the entire thing about washing clothes separately for unfathomable reasons (I mean, sharing bath water is fine ...).
So Wanko's just the status quo position (and I'd further say the whole 油断 - that's seems to me to be often used "around men", have your guard/defense up, don't be vulnerable; they are all wolves, and perverts, and rapists, they'll devour you if you are careless for a second ... others will better judge this but I feel it's more likely that it would have been phrased differently if it wasn't meant that way), and Elly goes "doesn't apply here because trans/girls (so not a boy and not dangerous)", only to then have that "oh wait, that's not necessarily meaning anything now that I think about it" moment.
But, eh. Whatever.