It's not uncommon for morons and douchebags to care deeply what people think of them. So you've just formed an observation that holds little meaning or value.
Maher has been around for decades despite that-- some might say because-- he has never feared to voice his beliefs without regard for whomever's jimmies it rustles. There are few other political pundits who could claim this.
Strange that as Maher aged he actually tilted more to the left, favoring greater government interventionist policies, against his earlier more libertarian tendencies, to the point he could no longer be accurately construed as anything but a staunch leftist, and yet by today's standards, because this country appears to be increasingly composed of douchebags and morons, who are stretching the left and right further and further apart, he is considered by many to be more of a left-centrist.
And that's why he's getting this hate. Because he's a centrist. There's nothing more controversial.
I'm reminded of that thread we had a few months ago about the right-wing guys who used an A.I. to automatically photoshop raunchy photos that women were uploading to social media to make them less slutty, covering them up with clothes, or putting them into domestic settings where they looked like well-adjusted mothers, and the feminazis online lost their minds. They foamed and frothed at the mouths about how evil the AI script was because it dared to imagine a world that preserved their modesty. Even leftists on this board noted how strangely ironic it was that this proved, today, the more risque way to portray women is to not sexualize them. Being slutty, being publicly naked, being pornographic...that's the status quo. No edge there, anymore.
To be a centrist right now is downright revolutionary. People will hate you for it. But what's so weird about that is: most people are centrists. They're just not loudmouths about it. Maher is.