Most probably the Switch cant do multitasking like the PS3/X360. Nintendo is still living in the Gamecube era. That is why the Switch cant run the game and the social app at the same time.
It certainly has the hardware to multitask. The operating system is derived from FreeBSD, which most certainly can multitask.
Multitasking is a shit excuse when even the original Xbox could multitask. (Playing back MP3's while gaming.)