I assume he meant that just because someone believes in something separate from their scientific work doesn't affect their credibility.
An easy thought experiment is if an astronomer believes that when an ostrich is scared it buries its head in the ground. Does this affect their work?
If a surgeon believes in destiny doesn't mean that their work is subpar or that they sabotage their work because it might be someone's destiny to die.
Idk man this seems pretty apolitical