When did this cuck thing become a thing, and how many folks understand its meaning and origin? Here's a hint: in and of itself, "cuck" is a recently derived perjorative with origins from the English cuckold, a man whose wife has taken a lover out of wedlock. In its present bastardized form it's taken on the meaning of a man of weak conviction, and worse yet, a man who may disagree with your strong conviction.
I don't have a point here beyond saying calling a someone a "cuck" is really weak sauce.