Language is very personal, and I like the diversity of the English language. I have no issue with people personally finding a term offensive if applied to them. In fact, when it comes to things like ASD/ASC which are hugely individual for each autistic person, each parent, each spouse, each (you get the picture), I think we have to recognise that it will be impossible to invent any term or small set of terms which would mean the same thing and be equally acceptable to everyone. It's not possible because our views and experiences are too diverse to be captured by one set of terms. Therefore I have an issue with dictating other people's language. It's more than telling other people what to say, it's telling them what to think, and how to see their life experience.
I'm a-okay with autistics. I really like it actually, I came across it first by American autistics (eg. Amethyst Schaber) but it's increasingly coming UK side now, and to me it's my community, I love being included in 'us autistics' etc .
I'm not an Autist, Autists pural just sounds not right to my ears, I'm not a person with autism. Nothing offensive at all to me about either of those terms, I just don't identify with them. I used to call myself an Aspie, but just stopped as I reached adulthood I think because it sounded a bit childish, I don't refer to myself as 'an autistic' either. What I am is an autistic person, part of a community of autistics, and that's how I like it. I want others to respect that, and by extension to respect that my life experience and thoughts aren't necessarily similar or can be mapped to theirs.
I'm a big believer in calling people as they want to be called. I completely respect that OP finds 'autistics'/'an autistic' offensive and so I would never be referring to OP as anything other than a person with autism/aspie/autistic person. Likewise I respect that some parents only feel comfortable about their children being called "people with autism" and thus I would only refer to their child as such (or simply as 'your daughter/son'!!), and all I ask is they respect that I am an autistic person in return, and not call me 'a person with autism' directly.
But respect should go both ways, so if you don't like a term or want it applied to you, you can't demand other people who may ONLY feel comfortable with that terms use yours instead. I am sure there are some autistic people who ONLY feel very comfortable with autistics plural as opposed to other plurals, and I respect them too. They don't have to make themselves uncomfortable for the benefit of other autistic people/people with autism (etc) or parents/professionals/anyone else, life's hard enough as it is.
I also agree with whoever said it's also about context, and that a sentence like "People with autism are usually savants" is much more offensive than "Some (but definitely not all) of us autistics don't enjoy making eye contact".
To draw the LGBT+ parallel again, I'm not queer simply because I don't personally identify with that word. I'm an autistic lesbian. But queer is an interesting word because for some people it's an offensive slur, whereas others find it to be pretty much the only word they are comfortable identifying with, and I (maybe naively) think or hope that there's room to respect everyone in a world which increasingly polices everyone's language - whatever subject and set of terms we're talking about.