**"If it's original works, and not actual content being ripped from the games, then I don't see where it would be considered anything other than fan art, and most people seem fine with fan art."**

Not a Copyright Attorney here, but it seems there are many "Fan art" precedents both inside and outside the poser/ Daz content communities that would support the above opinion

"I guess the problem is you never actually know if it's content that was ripped or content that was built from scratch unless you can look at each model and compare both."

Problem solved see attached:

"My understanding is that the other site in question directly rips content from various games (including Mass Effect and Skyrim) and sells it,"

No.......see attached.

My website

YouTube Channel