I read "progressive" as an ethical statement. Unless you can demonstrate a "scientific default" ethical system that all scientists should adhere to, this seems like valid distinction
Progressive means the scientists advocate reform or "new, liberal ideas". All of which is fine in their private capacity, but if these scientists are influenced in their scientific output by being progressive then they're not doing their job.
I don't really like to hear scientists described as progressive or non-progressive. I would prefer to hear that they are more or less sceptical.