It might not make sense as a policy, but honestly, only idiots would store any valuable piece of electronic equipment there and especially the larger the piece of equipment, the more idiotic. The person in the seat in front of you reclines suddenly or moves or leans or pushes in such a way as to damage it. Totally the responsbility and fault of the person who put it there. The person in the seat in front of you would have no responsibility IMO.
And somehow in my 3000+ flights - many of them with valuable pieces of electronic equipment in the seat back in front of me - not so much as a scratch.