You don't though. You have the right to not watch whatever you want, but if content is published with the value proposition that the ads and/or sponsorships are the price of admission, then it's hard to argue that you have the right to access the content anyway. Some publishers try to enforce restrictions like that, mostly ineffectively, and it's probably only because of technical challenges that more don't.
When you use YouTube you accept the terms and conditions (at least the parts that apply in your jurisdiction) which (probably) should state that you are not allowed to circumvent ads. If you do so you are in violation. Not sure what the consequences of that are though.
I'm sure all sorts of sites have magic words that claim I cannot block their ads. Meanwhile, some of them may have ad blocker detectors even if they don't have magic words. Either way, it's on them to show me or not show me whatever content they want, and on me to block ads or not and view their content or not.