Likewise for people vehemently advocating to disable SELinux, I view them with a great deal of suspicion. Is it simply they really do not like it, or do they have ulterior motives?
Neither. Initially, when trying to use it, they typically notice something stops working. Then, when trying to make it work, they get lost in arcane and cryptic tools.
You forgot the crucial point. Namely that SELinux is not necessary for most.
btw I don't know who "vehemently advocating to disable SELinux". Rather it is "I don't need it" or its variations -- all very smooth and mild like the Theodore Tso's comment I quoted in the first place. I quote one more from the same thread. This one is from Linus:
"I find SELinux to be so irrelevant to my usage that I don't use it at all"