Because real people have to deal with the real world as it is, not as they imagine it ought to be in their heads.
No amount of “it shouldn’t be like this” is going to convince a school full of kids in the heat of puberty to behave under those conditions.
Like how the real world paid her only slightly more than a intro fry cook salary to teach hundreds of kids so their parents could go be productive members of society for 8 hours, so she looked for other ways to supplement her income?
I’m going to get downvoted for this, but you’re speaking truth here. It sucks that she had to find something to supplement her income, and it is certainly a problem. That said, her starting an OnlyFans page was a poor choice on her part for all the reasons you laid out, and I’ll add one more: it increases the chance for her to be sexually assaulted by either a student, parent, or coworker. Also a very big problem. I’m not saying any of this is fair or just, it’s the reality of the world we live in. Fair or unfair, just or unjust, the choices we all make have repercussions. I don’t think it’s “fair” that she needed to supplement her income with a side hustle; but she’s not the only teacher who with a side gig, and most of them don’t wind up on OF. I don’t think it’s “just” that she was fired, but the kids at the school finding that content would’ve created a giant mess and possible legal situation for the school (which takes money from the already meager pot teacher pay comes from, i.e. tax revenue). Until the problems we all agree exist are addressed (sure, hold your breath waiting for that), the current reality simply cant be ignored out of idealism.