Politifact uses a secret monero miner to make money off of its visitors

What do The Pirate Bay and Politifact have in common? Sounds like the beginning of a bad joke, but the real answer is "a secret monero miner"!
Nowadays it seems to be the most popular way to make money off of your site visitors. Looks like a bad trend. CoinHive is the service that provides such websites the ability to place mining java script on their sites. CoinHive claims that their service is perfectly legitimate and takes a 30% fee for running their scripts. AdGuard recently revealed statistics that out of 100,000 top websites, 220 of them are using some kind of a Java-based miner. Seems like not a lot, but in numbers that's 500 million users.
The lawmakers seem to be lagging behind on handling this issue. It doesn't sound illegal right now, but the question of ethics still exists. I mean I wouldn't mind having a button "do you agree for this website to use your computer to mine or no?". Maybe I would click "yes", maybe I would click "no", but it should be up to the user to chose. It definitely feels wrong if I'm visiting a website, and some kind of a secret script makes money off of me without my knowledge. So be careful where you click!