Juniper has been moving out of FreeBSD for quite a while. See the link for some datail https://www.juniper.net/documentation/us/en/software/junos/o...
So GPL is not a problem for Juniper after all.
But even before that RE-S-2X00x6 cards were running FreeBSD on top of Linux KVM.
So no, network hardware vendors are not choosing BSD, not at all.