is there any actual data about that or is it urban myth?

Onlyfans keeps identity documents for its members so trafficking-wise they are actually safer than facebook. there are all other businesses affected by the same discrimination, e.g. sex toy shops, dating websites, nudist websites, basically anything that shows skin. I find it hard to believe that chargebacks are so much of an issue, especially since there are third parties willing to take the risk for a high fee (CCbill).