Do you not see the irony in what you typed ? Someone who thinks that the EU enforcing policy is ANY different to what the US does to the World on a daily basis :P
I don't complain, I just go "welp, looks like they couldn't be bothered to be careful with my data" and never go to that site again. Then I just find the same article on another website and read it there.
Anyway, the question is for people who do complain.
It is listening that is scarce. They can't expect that anyone will care.
As a side note, and to be picky, the site blocks visits from EU because of several concurrent reasons:
1) the site management cares about GDPR AND 2) they believe they would be infringing GDPR AND 3) they decided that it is not worth it to change so that it is GDPR compliant
I don't think that any of the EU members posting about an inaccessible site is actually complaining, I believe those posts are intended only as a notice, not different from the ones like "I cannot access that site with Safari" or "cannot scroll from mobile", statements of fact more than complaints.