Maybe it’s a nitpick, but it’s annoying having to get on road just to walk pass it.
Whenever cars obstruct sidewalks, I think about how it affects disabled people.
How does it affect a person in a wheelchair? A sight-impaired person? A person who has difficulty walking but is forced to park further away?
You're right, it's never nitpicking to complain about a person who parks on a sidewalk, or even about a person who partially obstructs a sidewalk, for example, with a massive trailer hitch on their massive eyesore of a pickup truck.
These people might be making somebody else's day much more difficult and stressful, in exchange for saving themselves a few seconds of walking. It's pathetic and it's the actions of a sociopath.