Perhaps, but I think you're reading more from that comment than was actually in the article. I can find quotes about generally saying the internet is broken, and promoting medium, but not specifically addressing flaws in Twitter.

I think that is the real problem, but I'm hesitant to say that's what their argument really is unless there's some actual evidence. At best, it's not backed up properly in the posted article, to the point of (to me) being highly misleading if their problems are with the lack of freedom in Twitter for one.