Telegram can feel free to block ISIS channels to disrupt them. However, they're not the problem and shouldn't feel morally obligated to solve it. If Telegram blocks them, they just use another app. It's that simple. If anything, U.S. intelligence should be exploiting the presence of ISIS on an insecure app as a way to track and fight ISIS.
The crypto concerns are valid, though. Telegram needs a professional audit.
I don't think a messaging app should stop illegal usage at all. Similar to ISPs.
> Telegram needs a professional audit.
According to https://www.eff.org/secure-messaging-scorecard there has been a recent code audit. I couldn't find more info though.
I agree, just saying that the article seems to suggest this. Like I said, there's been a lot of attempts to scare people about Telegram lately.
On the other hand, some others inevitably become collateral damage, using Telegram's (entirely) insecure defaults and thinking they have "secret" messages, or worse yet, enabling MTProto and believing they are safe in high-risk environments. Given this latest PR stunt, though, I think the benefits of Telegram's existence seem to outweigh its costs.