Putting a lid on propaganda isn't "controlling people". When propaganda is thrown at you from foreign states, those states are the ones attempting to control your population. Fighting that is defending your citizens.
How you fight is tricky and i don't agree that censorship is the right fix in the long run, but i don't think the person you are replying to thinks that either, it's just one easy way to combat some of it.
In USAs case I'm hardly allne in thinking that it definitely wasn't foreign states who got Trump elected. If so they must have been insanely clever because the Democrats outspent them by orders of magnitude AFAIK.
Trump got elected because people were tired of "politicians" and because Hillary messed up her campaign. Seriously: She was so close to winning it anyway that I like to think it was her calling a large chunk of her voter pool a "basked of deplorables" that got it over the edge.
How you fight is tricky and i don't agree that censorship is the right fix in the long run, but i don't think the person you are replying to thinks that either, it's just one easy way to combat some of it.