Is it acceptable to cut the extra ground tails after crimping?
I’ve done it that way my whole life.
No.
I use to do it that way until it was explained to me that ‘all’ conductors must be 6" long after entering the box or 3" passed the front of the box.
This is an incorrect method…the crimp is designed to fill it’s purpose and not be expanded on unless it is removed and re-crimped correctly.
As for the wires entering the box…yes they are WAY too short and are not 6" as mike has explained and they do not extend beyond the box either as Mike has explained.
The reasoning for this is the be able to service the device…if pulled out it must give clearance to be serviced and so on. While I do see the small 2-3" crimps stabs alot…I call them out when doing electrical pre-inspections.
Simply does not give the proper ability to service the wires and such…
Also if they bond this box correctly they do not need a pigtail to a GROUNDING receptacle due to the metal box…but again that depends on the NEC they are working from.
Check out 250.146(A) ( this was an revision from the 1999 to 2002 NEC)