Technology companies that make DPI technology for censorship should DIAF. If you work at one, you are actively making the world a shittier place. That is all.
Please don't post unsubstantive rants to HN. The idea here is: if you have a substantive point to make, to make it thoughtfully; and if you don't, then not to comment until you do.
I obviously don't know how they're actually doing it, but you can perform all kinds of analysis on traffic even when it's encrypted. You can look at the distribution of packet size, the time distribution of packets, you can analyze who is sending packets to whom. Traffic analysis like this has been a field of study since at least World War I. [0]
If you want to find Telegram traffic, you're probably looking at fairly small packets, often sent in bursts. If you're observing the sender and the receiver, you might be able to correlate the the outgoing messages from one user with the corresponding incoming messages of another user.
Of course, there are corresponding countermeasures Telegram could take: pad messages, combine messages, split messages, introduce random delays, distribute messages among a number of different endpoints. It's an endless game of cat and mouse.
It's not a good argument. Propaganda can always defeat morals, make people accept and do unspeakable things. Well, not all people, but still a lot of people.
Ever felt patriotic, proud of your country? That's how it starts.