I'm not sure whether I have experienced ableism or not. I mean, I got a lot of crap from both my father and my peers growing up, but nobody, including myself, knew I had ASD at the time, and I wasn't construed as having a learning disability or any other kind, except there was some limited intervention in primary school for my motor skills and also for a speech impediment. The intervention was successful speech wise, but my motor skills are still nothing to write home about.
It had certainly been observed that I could be quite obsessive and repetetitive about things and my hyperlexia was plain for all to see, but high-functioning autism wasn't on anyone's radar back then. Asperger's wasn't generally known, nor even diagnosable until 1994 when I was 14, and general awareness in education or anywhere else was very low for some years after that, so I'm not sure it could have happened any other way. (I was diagnosed at age 30)
Most people don't know I have ASD, and I'm not in the habit of telling them unless they have a very good reason to know. I get treated poorly by some, but it's difficult to tell whether this is from them perceiving (what is actually, but they probably don't know that) autistic traits, or just them being as*holes. In situations where high social performance is expected, yes I do get treated harshly when I fail, so perhaps I have experienced ableism? I've worked to engineer much of this pressure out of my life. I seem to manage to stumble my way through low-pressure job interviews well enough to get hired, at least in the IT sector where quirky/eccentric/awkward people are tolerated better than in some others.
In casual social interactions, it helps that my social skills have improved markedly over what they once were, mostly just from trial and error and copying patterns I observe to work well. Not that my performance is perfect by any stretch, but I seem to manage, especially one-on-one or in smaller groups. I'm not very outgoing, partly due to pre-existing social anxiety and partly due to sensory and processing issues; but being distant, withdrawn and having a somewhat flat affect is tolerated to a greater extent around here than many other places, especially in men.