I agree that the wheelchair logo should be limited to those with physical disabilities, but not only wheelchair users. For example, I walk with crutches and braces, and I think it still applies to me.

in the absence of a wide spread easily recognizable symbol for the mental health disabilities i think it is okay

My mom is on disability for her mental health, she quite literally cannot work because of it. She is disabled. She doesn't use the passes though. I do think it is also important to remember that most disabilities are invisible, someone can have a heart condition where they need close parking incase of an emergency but they look able bodied. If they have the pass and they use it then they need it.

That's the internalized ableism talking. If they don't match what you think a disabled person should look like, then they shouldn't say they're disabled. It happens to the best of us, but what's important is realizing that that's all it is and that people with crippling mental health conditions are just as disabled and entitled to accomodations as physically disabled people