Just because someone doesn’t meet your personal definition of disabled, doesn’t give you the right to judge them and deem them not disabled in your layperson’s court of disability law.
It is not your decision to make, nor your place to pass judgment based on your ignorance.
There are many ways someone can be disabled. That person you just made a rude comment to because they parked in a handicapped space deserves their parking placard. A doctor has to submit legal paperwork to the do in order for them to get one. Which means their doctor feels they are. Which means your ignorance is the problem, not them.
That person who looks “normal” to you but uses an electric cart while grocery shopping may not be able to push the weight of their cart as it fills. Just because you don’t see a cane or a walker, it doesn’t make your assumption about their abilities correct.
Before you decided on your own whether or not someone is disabled, stop and ask yourself what qualifies you to make such a decision? Why do you have such a narrow view of what counts as disabled?
There are so many disabilities that have no outward appearance. People with heart conditions may not be able to walk across the parking lot and still be able to walk through a store. You are not a cardiologist and you can’t judge the health of their heart from across the parking lot even if you were one.
People can have limited mobility while looking absolutely fine to you. They can have issues with organs that you can’t see. They may have diseases that attack their joints or ligaments and you have no way of knowing.
So, the next time you decided to be rude to that person who you have deemed to be “just fine,” ask yourself what makes you the end all be all judgment of what constitutes a disability? And what makes you so qualified that you feel you can accuse them of not being so.