A rose by any other name would smell as sweet. Ghostery doesn't want their bias to be obvious to the non-discerning user because it's obviously an attempt to reclaim market share using dirty tactics.
How are they "fighting one dirty tactic with another"? Clearly they are saying that the whole thing isn't a problem at all! They are fighting for manifest v3 with dirty tactics if anything.
They don't state they are testing their own product as far as I can tell. Strike one. They use a domain that says nothing about them being one of the tested products authors. Strike two. The whole thing is totally biased, testing apples against oranges and then posted to HN. Most papers would force them to have a "This is a paid ad" somewhere. Strike three and out.
I wouldn't really call promoting their own product on their own webpage an ad.