You can look at that statement in a couple of different ways. Yes, experimental bias is one of them. The other is saying: we didn't see this effect, so we need to do longer term studies to see if it does exist.

Regardless, that statement is a good thing. It acknowledges a social bias towards the effect of smartphones. It doesn't give room for people to imply a result based upon that bias. On the surface, at least, it doesn't indicate that data was fudged to reach a particular result.