In this instance (RT being banned), it's Russia's quite candid strategy to undermine social cohesion in their enemies' societies, using disinformation. Margarita Simonyan and Vladislav Surkov have each bragged about its success. So yes, for social cohesion, when there's a malign external actor poisoning public discourse with the intention of splitting societies, a responsible government ought to tackle it.
Information warfare is a real thing, and if you're suggesting governments shouldn't react to it - on the basis that doing so would fall under 'the old enemy of the people argument' - then what you're actually contending is that governments should neglect national defence.
If we start throwing around terms like "social cohesion" to justify censorship in the West, how can we complain about China doing the same in the name of "social harmony"?
I think your subtle arguments are wasted on EU's decision to stop the spread of misinformation and manipulation. It's that simple for them. Black and white. Us vs them. Don't think too much, you are taken care of by your "representatives" ...