No one has to like any author. I love Gabriel Garcia Marquez, for instance, and his style of writing usually divides readers squarely into camps of godlike worship or pronounced hatred. It is what it is.
As for Gaiman and this thread's topic, he does have some noticeable gender identity stuff in his writing, most prominently in the Sandman graphic novels. One of the Endless in the series, Desire, is explicitly gender-mutable, able to be both male and female or neither.
I don't think Gaiman is a great prose stylist, and the quality of his work varies for me. My favourite traditional novel of his is Stardust; I think American Gods is interesting theoretically but is not that well-written (though, to be fair, the standard available version of the novel appears to be an abridged version; there is a more recent "complete" version that Gaiman released that contains 12,000 or so additional words, which is supposed to be better than but not vastly different from the abridged edition). The Ocean at the End of the Lane, to me, is worth checking out. I like his Sandman series more than anything else he has done; my avatar, after all, is a version of Death of the Endless. His short stories I tend to find more interesting in idea than enjoyable to read or containing any sort of compelling characters; "Study in Emerald," for instance, is clever and interesting theoretically if you like Lovecraft, Conan Doyle's Sherlock Holmes stories, and historical mash-up fiction a la Kim Newman's Anno Dracula series, but it wouldn't do much for me if I wasn't already a fan in those areas, and so it functions more like niche fan fiction than anything else.
I appreciate the way Gaiman often tries to show that there is wonder in a world that can seem wonder-free, as well as his defenses of reading and libraries, and so he is sometimes useful to me (more for his essays and articles) when I teach freshman English/composition courses. But as a writer, I find him over-hyped, with the exception of for the Sandman series (and there, with the exception of the first graphic novel, which is nowhere near the quality of the ones to come).