For the sake of discussion, I don't think too many woodworkers would clamp that piece or moulding to the fence before making the cut for two practical reasons:
1) Some mouldings, because of their shapes, may not subject themselves to easy clamping. Imagine having to clamp and cut a dozen of pieces like that
2) The holding hand is safe from the blade, and if the grip is towards to fence and the stop, the piece shouldn't slip. (That might not be the case if the stop wasn't there.)
I've seen many unsafe cuts made, especially on a miter saw, but that one as shown in the photo wasn't one of those in my opinion.
A better way is to affix a strip of sandpaper or two to the fence for added purchase, if desired.
What caught my attention in the photo was the missing riving knife. For this kind of crosscut, I always use the dust collection blade guard, which does help a little bit in collecting dust.
