This expectation of sociability from one's fellow congregants is one of the most perfidious side effects
If expecting that people might attempt to practice "Christian brotherhood" in showing some welcome to Catholics lost in this time of crisis is what you call "one of the most perfidious side effects" of Vatican II then I would be led to think your views of Vatican II are not to be taken seriously.
of the perversion wreaked on the Faith and on the mind-set of the faithful by the horrid council convened 51 years ago.
So someone says hello to you. (it wouldn't be me) In your mind you're thinking. "This is the result of the perversion of the Council, that some impertinent person addresses me."
When Archbishop Lefebvre spoke and wrote of the NO mass as "Protestant" and "making Protestants," this social aspect was certainly not the main thing he had in mind. Yet this Protestant-style desire for "fellowship" as a prime motivation for attending Sunday "services" simply underlines the truth of his perception. People formed by the NO are, whether they see themselves as such or not, Protestant to the core. True conversion is much more than a matter of a few smells and bells.
What is resembles Protestantism is the social organization of many Trad chapels.