Sure, you can micro-parse the language, and yes, I mean it's at the 50% co-pay or whatever.

If I were trying to explain the rationale in this case, I'd theorize it's because this is typically something that happens once in a lifetime (if at all). I'd expect once one wisdom tooth gets cranky, they'd yank the rest at the same time. So, in this case, the thought would be that people partially pay for it when it happens rather than making everyone in the insurance pool pay for that risk every month, especially people with no wisdom teeth.

But I am not an actuary or insurer, so I don't know for sure.