That's disingenuous because you're omitting the other half of the transaction: You are choosing, voluntarily, to consume the content that they are offering on their website. The implied arrangement is that you watch the ads (at least the first five seconds until the skip button appears) in exchange for them doing all the work of collecting, hosting, and delivering that content to you.
Now obviously the financial value involved is de minimis in the case of a YouTube video, but nevertheless you're taking service and declining the payment.
The actual offense is so vanishingly small that they basically don't care enough to do anything about it, but let's be honest about what's really happening here. They're not just sending ads to you for no reason without your consent.