I agree advertising companies tend to be on the low ethical side of the spectrum, and often surf on the borderline of legal practices.
it doesn't in any way make those practice acceptable. but it doesn't grant another actor to step in and act in turn unethically.
I was thinking at first that any product that helps minimise ads and their diversion of attention is a win, but it's rather obvious that not any necessary evil is OK to exist so long as it fights another evil.
I find ublock origin doing its part without falling for the evil temptation. It's free and open source. I see little to no appeal to use a paid for ad blocker made by a developer with questionable ethics. even if that product happens to be superior. let's just make ublock better. and let's donate if we get value from it.
In fact, does ethics even exist as a concept in business, other than when it's used to sell more products?