Of course not. If we blamed the language for the bad actions of the people who spoke it during, there would be virtually no language left in a pristine enough condition to learn.
That being said, tempers can boil over. So maybe don't shout your Duolingo answers at a full Starbucks. I mean, that's good advice regardless of the language but you know what I mean.
I don't think those particular comments, in writing and devoid of tone, not meant for public distribution (and she's probably not running for political office or something justifying higher scrutiny), necessarily qualify as ableist per se, more skirting the line. I've said very dumb things in my youth and context is important, even in chat threads. But the rest of the picture you painted of that person is: asshole. So for my money it doesn't really matter if she ticked that particular box as well. Stay away.