That's a very common misconception and a stubborn myth: https://youtu.be/l_aFHrzSBrM

I fry mushrooms (and many other things) in olive oil all the time. It works great, tastes great and as long as you use extra virgin oil, doesn't create any more harmful substances than using rapeseed or sunflower seed oil, probably a lot fewer actually.

You can even deep fry in it, which some celebrated chefs do.