Hmm, depends on what you mean by anti hero. If you mean the kind who is basically a decent person who just has a major flaw they have trouble controlling, or who is on the outside of society, or who chooses to take extreme measures for the greater good, then it's not hard to make them relatable, even likable. Especially if the character grows or has a redemption arc of some kind.
But if you mean the kind of antihero who is genuinely evil, or who has goals most of us would think are evil, or who does genuinely and unambiguously evil things in pursuit of a more laudable goal? Well, there are plenty of examples of these too.
From what I've seen of this type of antihero who have been popular lately in fantasy, a lot of it resides in their voice or attitude. Their snark, wit and charm draw readers in, much as the snark, wit, and charm of real-live antisocial personality types can be appealing (at least in measured doses). They make the reader feel like they're part of an inner circle that really "gets" how things and people are, at least in the context of the story. And I suspect we all have a somewhat snarky or misanthropic voice inside our own heads at times, often triggered when people seem to be getting what we deem as excessively self-righteous, cute, or precious about something. As basically good people, we rarely (if ever) let that voice or attitude out to play, but it can be liberating to be temporarily drawn into a character who does.
Just my thoughts on it.