Bagpuss
Legend
This seems far fetched, to be honest. How could WotC be liable for OGL content?
Because they have given them a license to use their work which it is based off. They have said it's okay it's official OGL content licensed under OGL1.0a
Now if your are going to sue about product do you go after the small 3 party with limited resources, or do you go after the bigger corp that will settle out of court to avoid having their brand associated with whatever product is objectionable?
They don't even need to be liable they just don't want it getting in the press and tarnishing the brand. They are looking for D&D to be the next Marvel/Disney they need to make it family friendly and clean it up. It's daft but it likely is how lawyers and execs that came up with this mess are thinking.