High chargebacks in high-risk industries are related to three things:

1) The goods are digital and delivered immediately. This means that if I just got a hold of a 100 stolen CC numbers and want to test whether or not they're legit before moving on to physical goods, I'm going to test them out at one such service - which shoots up the CB/refund rate.

2) This also creates a secondary market for illicitly opened accounts / access, which is easy money (and anything else you can imagine down the lane on piracy etc.)

3) Because the margins are so low due to high marketing costs + competition, many sites (especially in the past) would sign the user up to endless recurring billing schemes which are nigh impossible (or costly) to cancel, also driving up the chargeback rate.