I'm going to need a citation for that. I don't use ABP for obvious reasons, but I don't really see them as a problem; they're effectively extorting money from advertising companies, which are absolute scum and deserve to lose any and all profits that they have made (not only for scummy business practices and an entire business model built around the worst kind of psychological manipulation and data mining, but actually convincing people that they are good for supporting a "free web" as if they are some charitable benefactors giving free money out of the good of their hearts). The enemy of my enemy is my friend.
I haven't been able to suss out any way that they do any real harm to the end users, but if they do actually do harm to other ad blockers, that would be some actual harm, but I am having trouble finding any evidence of this anywhere.