Assange has also worked directly on russian payroll (he had a program on RT) and has basically admitted that he supports russian imperialism (not in such an explicit manner, but we are all adults here). Not to mention he had no issues undermining the safety of whole multitude of people in his leaks as part of his quest for fame.
Snowden knew (or should have known) what he is signing up for. Collaborating with the russians (whose internal control of local internet services and jailing of people for social media posts makes the US look reasonable and human rights focused) is not right.
And even from a pragmatic standpoint; let's say I believed all the stories about Snowden not having any other options (I speculate that he actually supports russian imperialism and their methods); why should anything he says be given any attention?
Tomorrow the russians might tell him that he needs to promote that Stallman is evil pedophile and Adobe are a great company. You're saying he will suddenly reject their orders and refuse to execute them?
What is your logic here?
Nah, your logic is virtue signalling.
You don't want compromised inviduals promoting your points; there are many other who have a measure of consistency in their beliefs and don't back down (to a regime that makes US surveillance seem like a walk in the park) at the first sign of trouble.
If you don't want to make such choices, then don't get involved in activism. It's very simple.