Propaganda is still dangerous, and a country at war has no obligation to allow the country it is at war with to continue to openly spread it. Banning RT makes sense in that context.
I don't see the banning of Al Jazeera in the same light, as it's not like it's a Hamas-run outlet.
A country at war has no moral or legal obligation to publish its enemy’s propaganda. This should be very obvious.
And yes RT was always complete shite for gullible morons, though it is rather beside the point in this case actually. The British government had no moral obligation on free speech grounds to allow the spread of nazi propaganda in the United Kingdom during WW2, either. Again, obvious stuff.
Propaganda in war times is very often directed at a domestic audience. Examples are stories like the Ghost of Kyiv on the "western side". There are examples on the Russian side too.
Yes: A lie to boost the morale of a country fighting a defensive war against a genocidal dictatorship is unambiguously a better lie than the lies of the genocidal dictatorship to rile up its populace to more effectively execute the genocidal war.
My country lied to its populace during WW2 to boost morale in its fight against Nazi Germany. Nazi Germany lied to its populace to more effectively execute the holocaust. They are not the same.
So it's true, not all lies are equally bad, hope that helps. Most learn that as children.