I can't speak for the GP, but in this case of the cryptocurrency sites/fora I frequent (including topical subreddits), the ads are for idiotic scams. This indi

I can't speak for the GP, but in this case of the cryptocurrency sites/fora I frequent (including topical subreddits), the ads are for idiotic scams. This indicates that whatever vetting they're doing is insufficient, and so they can be safely blocked (specifically -- if they can't be trusted to not display ads for obvious fraud, they can't be trusted to vet ads for other malicious attributes).