Muslims get grouped into a single category in the US because we treat their religious beliefs as monolithic
To be fair, we do the same with Christians, often you'll hear someone just say "Christians" (or bible thumpers, Jesus freaks, etc), we talk as if the Catholics are the exact same as the Baptists, but only one of those says dancing is a sin, and the other shuffles around pedophiles.
Hell I done did it again above, by grouping Judaism, Christianity, and Islam as books one, two, and three of "The Abrahamic Religions" (the three monotheistic religions that view Abraham as a prophet). It happens. We only get more specific when it's necessary (as in talking about snake handlers specifically will result in the word Pentacostal being thrown out), but typically people just say "Christians" and group them all, pretending we don't is intellectual dishonesty because we can't criticise one freely as we can the other, because only one can skirt most criticism by claiming racism while the other is fair game (in fact ALL religions are fair game apparently, besides two of three Abrahamic ones...)
And you do it too:
Muslims as a single category
So we can group them by the larger group, rather than their smaller subgroups?
LGBTQ+ people
literally grouping Lesbian, Gay, Bi, Trans, Queer, and + people by acronym despite the fact we both acknowledge individuality as a thing.
Evangelical Christians
Baptists, Lutherans, Methodists, Presbys, Pentacostals, which one are we referring to again? "Evangelical" is just a grouping of protestant religions that have many differences despite their commonalities.
And finally: Are we cool with self reported studies now? Every time I use one someone comes along to remind us just how inefficient that method is for finding true answers to questions because people do a thing called "lying" on them frequently. It's possible that those reporting their feelings on the survey are grouped otherwise, as in they sourced their call list from a list of otherwise likeminded individuals [like if I put it on Home & Garden's website I'd get mostly replies from suburban ladies].
If we are, then "cool," but it is interesting how it was 68% muslim acceptance of gays in 2015, and then they backslid to 56% in 2023 and then back up a bit to 60% in 2024. And btw, being at 60%, they only beat the two worst religions on the list, "evangelicals" (which again is one of those groupings we "don't" do) and Jehovah's Witnesses, literally the two who if you asked ANYONE ELSE "who are the worst, most insane Christians" you'd get those two as an answer, probably not the flex it seems like tbh, basically "well they're bad but not as bad as the two worst ones" puts them at "3rd worst," at best.