If you replace "quirkless" with "autistic", it's the same argument and I hate it. I am autistic. I do consider it a disability. But almost paradoxically, I am not disabled by my autism, but by the society that by and large refuses to accommodate my autism. If I had the option to cure my autism, I'd say "hell no", because it's part of who I am as a person. And the "cure" for both autism and quirklessness both boil down to a robust eugenics program.
Eugenics is more "prevention" than cure, technically speaking. I mean, you can't use it to "cure" people who already have the condition after all.
...well, maybe you could with sufficiently advanced genetic engineering, but that's a different thing.
Mental conditions/disabilities are a more delicate topic, I think. It's easier to point at someone born blind and say "curing that is objectively good".
With mental conditions... well, I don't know. I admittedly don't know any autistic people I think, and I agree that a big part of the problem is more in how society treats people with these kinds of conditions rather than in the condition itself... at least some of the time, and for some of the conditions.
Though if you consider it a disability, I find it a bit weird you say you wouldn't want to be "cured" of it. Then again, people are always scared of change, and especially of changes to something so... personal/intimate/Idonthaveagoodwordforit.
Ideally I think the best thing would be to have a way to experience what having AND not having any specific mental condition feels like, and then decide based on personal experience... but ignoring how that might just be impossible, then there's also the problem of "what if "me with autism" has a different opinion from "me without autism""? Who has the right to choose, there?
...I'm digressing a bit I think. And let me be clear I'm not trying to offend anyone, just in case.
With things like Autism specifically I think the topic is even more complex, because as far as I know people with similar conditions sometimes have special abilities/gifts in specific fields, so you can't even argue that it's an objectively worse condition. It's more of a trade-off, lower social abilities for better abilities in different fields.
I will at the very least agree with the "you can't force a cure on someone" though. No matter your opinion on their condition. Not unless they're explicitly a danger to both themselves and others, like in some kinds of insanities, which is a completely different thing anyway.