That is harder to justify. Tracking is an invasion of privacy, so blocking of trackers can be seen as a defense. But blocking non-tracking ads, just because us

That is harder to justify. Tracking is an invasion of privacy, so blocking of trackers can be seen as a defense. But blocking non-tracking ads, just because users don't like them and Mozilla could make a buck, would be seen an attack on publishers' revenue, even when publishers tried to do the right thing.