I think it's more complicated than that. Divide it into cases.

Most teachers and students don't want to have sex with each other (duh). In many cases, they both do, and if they can succeed in keeping it quiet, all will be well.

The interesting cases involve conflict.

Let's consider the case of a student who wants sex and a teacher who doesn't. Our common cultural pattern is that women don't usually want to just get laid by men who don't want to. If the man is strongly tempted and determined to resist, she might want to get him over his resistance to get the relationship she wants. But if she is goodhearted, then whether she succeeds or not all will be OK.

There are of course women who will claim teachers harassed them when they didn't, or who regret a break-up and recast a consensual relationship as coerced. It's a real problem. I suppose some students will threaten exposure and coerce the teacher into giving them a good grade. Doesn't sound too frequent or too serious if he goes along. But if she pushes the issue, it is PUBLIC and open. The student appeals to society at large to condemn the man.

There are also well-meaning men who might ask a student if she wants a relationship, she says no, he accepts it and continues to treat her fairly. That's OK if she is confident he will be good-hearted about it.

But there is the other case where a man wants sex and coerces a student into it. She is coerced, says nothing, and it remains a PRIVATE matter. The cultural pattern says it is common for a man to be interested in sex with an unenthusiastic partner. We on the outside won't hear about specific cases, but by anonymous reporting it happens a lot.

There is huge variety in how these things play out. You folks can point to news stories of horrible injustices. Women can point to public stories of injustice too (like coercion and rape in the military). But the vast majority of cases will stay silent and involve men coercing women.