It doesn't matter how real a risk it is. It's "suspicious" and that's plenty enough cause to harass people in the post-9/11 security theatre. Nobody ever got fired for choosing IBM, and [almost] nobody ever got fired for being "too cautious".

All is fair in love and security theatre, I suppose

At this point my baseline assumption is that anything that receives TSA attention is not a real risk. What this is is a concrete thing that they can point to to justify their existence, even if the thing isn't a real threat and shouldn't actually help to justify their existence.