I’ve always wondered about this. Is there a specific scientific reason humans are so affected by music?
Psychological conditioning? We see images of people dancing and/or tapping feet to music, and thus, do it ourselves. Just a WAG.
I see this as a part of the larger question; why do we enjoy music at all?
I personally have no idea.
Don’t know why we seem compelled to do it, but my 7th grade band teacher (way back when) would have fits over this as it always sounded like a company of Marines was parading through the classroom while we were paying. 
Anyone remember that scene from Gone With The Wind? To override those Southern ‘rules’ of decor, it must be pretty deeply ingrained.