I think he would be, if not for the fact that he's the richest man alive and has virtually unlimited resources (as well as a growing friendship with the potential next president of the United States). Pavel Durov, he is wealthy, but nowhere near as wealthy as Elon. Plus, Elon's business ventures span more industries than Pavel's. That means that arresting him would cause more of an economic reaction than arresting a man who runs a chat app.

Now, if we're talking cause, it's definitely 100% political. The fact that Discord and Facebook propagate far more illegal materials than Telegram, yet neither company is in legal trouble over it, tells you all you need to know. Telegram may not be the best app for privacy, but they didn't really censor political speech, and I think that is the number one cause for Durov's arrest.