I block ads because they annoy me. Maybe I'm completely selfish but I don't give a shit that whoever I'm "freeloading" from isn't receiving any compensation.
I also download books, music and software because if I can get something for free, I'm not going to pay for it (don't care about the content creator, this is purely selfish). I also download movies because it's free, and series because it's free and devoid of ads (which waste my time and I don't care for). Even if you made paying easier, if there's a reasonably easy alternative to getting it for free, I'm going to use it.
Why? Because it leaves me with more money to spend on shit I can't get for free.