All of these people have something wrong going on; believe me, I am much more aware of "mood lability" in the general public since I became a therapist. Before, I just thought these were rude or weird people. But the behavior fits a pattern, that is easily recognizable to mental health professionals. I'd hate to think that it's being attributed to "older" women, of which I am one. I would never comment on anyone's bike, or anything about their riding on a group ride, unless I thought I was in danger because of their poor riding skills. I might think it, but I wouldn't say it....
All of these examples have the same symptoms; irritability, unexplained anger and the need to put others down. I'd bet in most cases it's because someone has put them down in the past (or currently), or they are afraid they might not measure up to a new person, so they lash out, instead. Sadly, I do find women do a lot more of this, in social situations. It might be because women generally are predisposed to having issues with depression/poor self esteem.
I'd just stay away and not engage with the person. Although, Marni's comment might make someone "snap out of it."