Google does not send emails to spam just because it doesn't like the politics of what is being said in the email, so no, it's not the same thing.
Also when Google sends something to spam you can still read it. What "Amnesty International" is asking for here is making it impossible for people to read what some people say.
Spam is by definition messages that the recipient does not want to receive. Given what happened in Myanmar it looks like these people did want to receive those messages - but some organisations like "Amnesty International" didn't want those users to receive those messages. That is not a spam issue, that is a censorship issue.
