let them in. asexuality is a hard thing to dice. you don't have to face a certain degree of oppression just to be able to fit into the lgbt+ community. and asexuality is something considered "not the norm" in terms of sexuality. like i said, it can be a difficult thing to dice and a hard thing to come into and figure out that you are, especially when we live in a society so sex-heavy. it's akin to, say, being comp het in a sense.
i think it's absolutely nonsensical to shun a group from the community on the basis of "oh they didn't struggle enough" or "their lack of sexual attraction doesn't mean anything" like. that's ridiculous. and in the former case, that's like saying bisexual people in het passing relationships don't count when they're literally a part of the main acronym. in the case of the latter, it's...not a fun realization to come to, especially if you've been with someone for years and you're like WOW i sure 8) can't do this thing 8) feels like fuckin shit. you feel like something is wrong with you -- which is a common thought when you're going through the "am i gay/trans/whatever" process too. it shouldn't be a thought, because nothing is wrong with any of these identities. but anything that's not cis or het tends to go through a 'this is wrong and i'm wrong' mindset, especially depending on where and how you grew up.
tl;dr we should be uplifting each other, not gatekeeping. there are things that obviously do not belong in the lgbt+ community, but asexuality isn't one of them. i've always thought the a in the longer acronym was for aces anyway? hm.