Navalny was a CIA and MI6 asset. He was also a criminal that scammed people out of millions for his bogus "Anti-Corruption" group. He was a horrible racist, xenophobe and homophobe who called Muslims insects and worse.

He was not a nice guy, and he certainly never posed any sort of political threat to Putin.

Here he went to CIA boot camp, where they teach you about color revolutions:

Navalny was, at one time, the West’s candidate to lead the new Russia once Putin had been removed. Now he is a widely known CIA asset with no following in Russia at all. [Source: Yale]