Maybe not specifically to be loud about, but I do think it appeals to some people specifically to be able to claim or feel a sense of moral superiority. I was molested as a child and spent some years wanting to be vegetarian in part due to wanting to find some means to feel "pure." I am hardly unique in having grown up with a lot of emotional baggage. Most people are raised with either a shame or a guilt model. I think trying to find some resolution for having had that hung on them is a big motivator for a great many life choices in the world.