I have seen some of this with "nonbeliever" vs "atheist." A lot of people see "atheist" as harsher and more definitive than "nonbeliever" even though they both essentially the same. (I guess you can be a nonbeliever who does religious stuff but doesn't believe in it.)
I am seeing dispute between "bisexual", "pansexual" and "omnisexual" lately. This is based on some negative views of bisexuality which is associated with being more sluttish. In addition, the other words imply a gender blind appproach to sexuality.
I remember when "negro" was a polite word. I never liked "African American" since it could apply to people from Egypt and it implied a dual citizenship.
There are a lot of subtle nuances when we pick labels. I think it is very natural for each label or category to morph over time and for people to want to change the name to keep the idea fresh.