To be fair, if you want to have access to the forum without paying, you don’t really have a right to tell the owners how much of the space they should be able to monetize. It’s their business model. I was a tier one supporter when it first came in, let it lapse to see how much I would enjoy the place without paying, decided I didn’t like it much, so became a tier one supporter again.
Your choice is between paying to have an ad-free experience or a pay-free experience, but you don’t get to choose how much money the owners earn from your presence here if you don’t pay.
FWIW, I agree that the pages are heavy on ads, but that’s the owners’ business, not mine, and I certainly wouldn’t dream of telling them that they should earn less money from the free version.
My guess is that they earn nothing like as much from the ads you see as they do from the subscribers.