Maybe he felt like there's no need for any tactics on trash. I wouldn't be so bold to do that in ops, but in FPs, when I know it will make zero difference, I'll pull before tank without thinking twice.
IF you are all lvl 55 or most of you, why not? I'd do that as well just for the fun of it. There is not more better chances for lvl 55 sorc to enjoy his lightsaber than lvl 50 FP.
Your yardstick of "good group behavior" could use some adjustment.
Derping just for the lulz should be saved for runs with friends. If you're in a pug group, it's better to have a little more courtesy and professionalism.