Is the issue is whether the official reads someone's messages, or whether their critic's messages show up for others to see?
That's a rather cynical take. Imagine a politician you disagree with - be they a fascist, communist, libertarian, or whatever - tweeting something blatantly false. And imagine that they block replies by everyone who contradicts them, making their replies a chorus of agreement. Wouldn't that seem to be an impediment to civil discourse?
Indeed.
https://knightcolumbia.org/content/knight-institute-v-trump-...