This is very much a Japanese cultural issue that still doesn't really have an american equivalent, but it's been visible in manga since at LEAST the early 90s where it was Ranma's primary insult vs Akane, or even further back in the 80s with Urusei Yatsura with Ryuunosuke. If you want an extreme example though, Utena qualifies.
For a second there I thought the guy talking from page 1 would be the protagonist, until I saw the fat old man on the 3rd page.
Also, man, the male students just don't get it, especially based on their comments on the last page. If even one of you had bothered to maybe try looking a little closer to find out how cute she is, she wouldn't be with the Janitor man.
He's honestly just stocky, not fat for once, as he's clearly actually been doing his job while harassing other girls for who knows how long til he won the lotto with her.
O-Kay ... how should we classify Janitor-san: (1) "You're Despicable!" (2) "You Lucky Bastard (GRR)!" (3) "WHY NOT BOTH?"
Whatever the case, the (a-hem) "stress relief" from maintaining her public image seems to be doing Amane-chan a world of good, plus it seems that (a-hem, again): "Hey Mikey, I Think She Likes It!"