Because there was less importance in swingblocking outside of saber vs. saber combat than there is now. More people swingblock than before, for the advantages that it offers.If you hit a saber wielding opponent midswing with lightning it no longer stuns them as it did in the past. Also if you grip superpush an opponent, who is holding block while being gripped, the 2 handed push animation still works but they are left unharmed.
It doesn't stun when they are 0 force power and not swingblocking; I have tested thisIt does stun when you aren't swingblocking if you are force focused or don't have enough FP with regard to your Force Block level.