I don't get it. You decide to approach someone that you do not know, to ask them to do you a favor. If "she did not even turn around", that suggests that you didn't even bother to make eye contact with her before imposing on her with your request -- a request that would trouble many people. (Why don't you take your bike with you? Why don't you have a bike lock? When are you coming back? Is it even your bike?) When she choses not to be imposed upon by a stranger, your response is anger -- and some sense that your anger and your rudeness is justified. Which, to me, suggests that her reluctance to do a favor for a complete stranger is -- at least in part -- good judgement.
I'm startled by your inability to imagine this situation from her point of view. So yeah, she could have been nicer, but you had already imposed upon her -- and perhaps even ignored clear signals from her (such as lack of eye contact, and not responding to your initial comment) that she did not want to be approached by a stranger -- or imposed upon. Whew. So, put yourself in HER shoes. This may have nothing to do with your "disability", or your race. It certainly has nothing to do with you being "picked on". This woman didn't even know you -- much less your personal history.
If this is an example of what it means to be "pretty much a nice guy to everybody", well, I guess we have VERY different standards. Reading this has reminded me why "don't talk to strangers" is a very good rule.