It should be like that, but ad platforms are engaging not just in a cat-and-mouse game of ad blockers but also ad impression fraud (their words, not mine). This

It should be like that, but ad platforms are engaging not just in a cat-and-mouse game of ad blockers but also ad impression fraud (their words, not mine). This is why the JS loaded from ad servers are huge - they're trying to detect if it's an actual user or scripted click, which ironically pushes users to block ads wholesale due to these heavy and genuinely CPU-eating JS blobs.