Under its past owner Evidon, their business model was based on selling data to advertisers.

Starting 2018, they showed personalized ads by themselves, through the GhosteryRewards program. I think that has since been terminated, but it would comply with the FAQ you posted (they claimed that personalization was purely on-device).

I don’t know of any current offending practices, but there is no reason to trust or support this enterprise in the presence of better alternatives. uBlock Origin never did any of that, avoids all shadow of conflict of interest, and works better.