[gwern]

> So now we know that sites target this bit to block, but the real question is why? Is it that someone didn’t see the date of the RFC, maybe sarcasm doesn’t translate very well, possibly someone in the real world actually sent the evil bit when doing evil things, and cause some products to target it?

The evil bit could be something of a self-fulfilling prophecy. Because no one uses it, that makes it a source of bugs/vulnerabilities; therefore, anyone setting it deliberately but not maliciously (such as for a joke) will want to turn it off; only those who want to exploit it maliciously will keep it turned on; hence, anything with an evil bit can be safely assumed to be, in fact, evil, and it should be filtered out automatically.