Let's say we don't trust ublock. At the very least it is still blocking ad networks which do reduce internet performance and are vectors of exploitation, so it is still adding value whether you trust it or not.

Under the hypothetical that we don't trust ublock, it would be foolish to grant it full access to all data on all websites. It would not be adding value.

Yeah — they’d be selling enhanced versions of that data to every site they blocked, and then some. I very much doubt they are.

I mean, I don't trust ublock, for what it's worth. I just disable javascript by default with has pretty much the same effect.