Maher's views on vaccines have always been questionable, long before the pandemic.
He's never been a full-on Jenny McCarthy-style anti-vaxxer, but he's certainly flirted with that viewpoint.
His opinions on medical and health issues have always been pure shite, so none of this is new.
Also, he's a stand-up comedian, and many, many stand-up comedians, no matter how liberal, adopted the anti-mask, anti-precautions stance of the MAGA world, because their livelihood was threatened, and they couldn't go out on the road and work in front of audiences. Maher at least still had his TV show he could do, unlike most comics, but he wasn't happy about having to do it alone in his backyard, interviewing guests over Skype, with no audience to interact with. His show sucked during that period, and he knew it, so now he rails against the COVID "overreaction".
He also has always had this tendency to grab onto one topic and beat it into the ground. A couple of years ago, it was "Trump isn't going to leave office, even if he loses". Every week, every show, over and over, until everybody got sick of hearing about it. (Of course, as it turns out, he was more or less right on that one...)
This season, it's the "woke" stuff.
But at the same time, you gotta laugh at people who think Maher is MAGA. He still hates Trump with a passion.