I tend to be of the opinion that the recliner camp is made up of people who perhaps don’t fly very often and therefore don’t get quite how irritating it can be.
Don't be silly. I fly once a month and long haul and super-long haul several times a year, and have done so for about 40 years. I don't think reclining is rude, I do it, and I don't resent people who do it (unless at meal times).
I do think anyone (child or adult) who kicks the seat in front of them is beyond rude, however. Also those who grab the back of the seat in front of them as they get in & out of their seat, instead of grabbing the back of their own seat. THat's VERY rude.