Because that's what happens if you don't have web advertising. Free things disappear without revenue.
Or maybe you'd prefer to go back to the days of randomly-targeted or "PUNCH THE MONKEY" ads. Because THAT'S what happens without ad auctions and targeting.
The reality is: advertisers and ad-supported sites WANT to show you a relevant ad that you're likely to click (modulo obvious bad actors). That's how they get paid. Anything else is, by definition, "[wasting] users' time and attention."