Maybe. It definitely can hurt in various ways, including how it hurt me. The difficult question is whether the expected hurt is more than the expected reduction in hurt, and best guess seems to be that it's too difficult to tell in general from the evidence we have so far, so no one should be promoting these things until we can show they're at least safe.It's not always just yourself that you may be helping. If wearing one makes someone else at ease over you cycling, would it hurt?
But being asked to parade around in it and laughed at sounds to me like there may be other reasons for the demand, such as discouraging cycling. I hope I'm wrong.