Re: I don't believe it.
To some extent you're right, but the article was about Reddit saying they've identified and banned accounts such as this, mostly before the 2016 US election. Essentially framing it as a past, dealt-with problem. Clearly, in reality, it is an on going issue.
Separately, it may be true that combating extremism with truth is one tactic, but it's not the only one. In this case, these posts are not organic views from withing a country, open to reasonable debate. They are state-sponsored messages from a hostile country, aimed at sowing discontent and division. They are not open to debate or reason, and they are not "real" views. Banning them is the only reasonable approach. And although the one I linked to is crude and obvious, there are many who are better at it than this guy.