Traffic quality analysis is often far worse at a lot of these sorts of companies than you'd expect. I wouldn't be surprised if they didn't have an accurate analysis on the full scope of bots on their network.
Consider that if they study the problem they may discover the problem is severe and they can't fix it. Now they have an even more serious problem: If they lie about the existence of the report, they're defrauding advertisers. If they admit the contents of the report, advertisers and users will flee.
So it's rational for them to not look in the first place. If they don't know, then they're not technically lying. This is good for them, but nobody else.