Yeah I was a bit surprised when I read the article and what they're complaining about is being demonetised. Not blocked.
I don't think this constitutes censorship. They can still publish what they want. They just don't get paid for it this way. If what they have to say it's that important, does it really matter? If they're indeed scientists, don't they have a day job doing science?
I'm all for free speech but getting paid for it is another issue altogether IMO. Still an ethical topic worth debating, but not a free speech issue.