They practiced Communism as a religion. An orthodoxy had to be followed and grave consequences for those who didn’t.
Who is the god of communism?
“The continuous disasters of man’s history are mainly due to his
excessive capacity and urge to become identified with a tribe, nation,
church or cause, and to espouse its credo uncritically and
enthusiastically, even if its tenets are contrary to reason, devoid of
self-interest and detrimental to the claims of self-preservation. We
are thus driven to the unfashionable conclusion that the trouble with
our species is not an excess of aggression, but an excess capacity for
fanatical devotion.”
— Arthur Koestler