It seems to me that it's a timeless phenomenon, rather than a recent evolution. If you announce something along the lines of "Group X's beliefs are really Stupid, LOL, and they should just GET that and drop their STUPID beliefs
," well, chances are, Group X is not going to be able to discern any lighthearted humor in your remarks.
Anyway, I'm not even in the Group X you've been recently making fun of, and I don't see a whole lot of lighthearted humor in what you say about their beliefs -- a lot of what you say about religion strikes me as very angry and mean-spirited, and I don't think I'm alone in that. Why would people respond with good humor to what they perceive as anger and mean-spirit?