alt Hacker NewsI think you're reading the wrong motivation into this and reaching the wrong conclusion.
This behavior, being skeptical and precise, is the very thing that makes scientists more trustworthy than the average Joe with his motivated reasoning.
I'm confident that the people working on this would have made the causal claim if they had been able to collect enough data to support it. They may well be working on gathering data to support the causal claim right now.
This technically useful skepticism can be weaponized against you by a rhetorical opponent by just pointing out that you "refuse to say for certain". All you have to do is say "some scientists believe there is some uncertainty" and you can convince a crowd to stop listening. Scientific communication works very poorly as mass communication.