Developer A makes a move, perceives some benefit, tells developer B, who does the same thing and then tells developer C.

Some of the people consider the move, weigh costs, and make an intelligent decision. Many just think "smart people are doing this, I'll do it too". I really doubt this behavior is unique to developers.

Statistically I would assume that if you select a bunch of people on a certain criterium, you're going to see similarities related to that criterium among that group.