I believe the opening sequence was enough for a PG-13 rating:

old man being killed (off screen though) ;
villagers being executed (off screen again but the amount of violence implied is enough) ;
and there is the dying trooper finger painting blood on Finn’s helmet ;
not to mention the frighten and desparate alien being arrested by the troopers.

And yeah the first mind probing sequence is cherry on top. You also get three guys (one trooper by Finn, one samurai guy in Rey’s vision, and Indiana Jones) getting saber pierced in front shots.

It’s not as violent as ROTS is, but I can understand the rating… in the US/UK at least.