They could be copright trolls who are trying to force Steam to do just what they did so they can claim damages for lost revenue on delays on actually legitimate claims. It might be a bet on how well they think they will be able to defend against perjury from the people actually able to sue. Mods aren't like YouTube channels, a lot of them aren't getting a decent revenue stream that they claim they lost or to help them in their defense.

THIS shit is why Steam continues to dominate the market. I have a healthy wariness of Steam's ubiquity and power within the industry, but they continue to prove that they got it for a reason. Imagine if fucking YouTube treated DMCA trolls this way.