Not an expert, but how would you incite a riot with the telephone? It just doesn't work.
TV is a closer analogy, but back in the days of broadcast TV, you had to get airtime with one of a dozen networks. (And Trump did this! He had the number 1 show on TV for awhile in the early 2000's. He continued building his brand as a "rich guy who makes deals" there.)
You can't just come back the next day and broadcast another message, i.e. testing what works and iterating. It takes a whole team of people to make a broadcast. Also, the audience would watch TV at home; they didn't have a device to consume the message anywhere. It was fundamentally slower.
Even blogs are slower, although you can definitely get deplatformed for a blog. Blogs lack discoverability; they don't broadcast to followers. In the heyday of blogs most people weren't reading them on their phone.
So social media, and Twitter in particular, is a really effective communication technology for broadcasting sharp messages.
Telephones do have similar issues -- there is a reason that wiretaps exist and that traditionally the phone company was a monopoly with close ties to the government. But they're not a "platform" for broadcast.
I think the point of Yishan's post is that social networks are not the equivalent of telephone companies, they're their own thing and can't really be compared to what came before or treated as such.
