They have to remove the risk of being labeled anti-party or dissidents. They do this by appealing to the ideology, at least superficially.

Of course, this is a double edge play. Notice how the message boils down to “the party is right! It’s probably the fault of some dark, greedy figure(s) somewhere!”. But by absolving the government from ever being wrong you remove the possibility of them ever improving and fixing themselves. So someone(s) get sent to jail, others are demoted, and everything is swept unde the rug, but the structural problems remain and will appear again and again.