The first lab mouse I touched had soft white fur and a light pink tail. It looked cute enough to snuggle and take home as a pet and I was smitten. I slipped my hand into the cage, thinking the mouse would respond like my pet gerbils or my brother's pet rat. As my hand closed around its belly, that sweet little mouse sunk its teeth deep in my thumb. I screamed and shook my hand, smashing the mouse on the cement floor and killing it in an instant.
It's been many years now since I've been doing anything with mice or rats. There's much more oversight these days, as DrugMonkey has been describing in detail here and here. It seems reasonable that part of that oversight might include requiring students or technicians to complete courses in animal handling before they work with animals. The Blue Lab coats describe an additional course in bioethics that covers animal work.
One of the commenters on an earlier post mentioned that some researchers seemed a bit too callous when they were working with animals and were doing some uneccessary things. Maybe they were, or maybe like me, they were just ignorant. In my case, I had all kinds of good intentions, but I didn't know the proper technique for mouse handling. My thumb hurt like crazy, but I sure hadn't wanted to kill the mouse.
And maybe courses in animal handling could also include some advice on how to talk to your colleagues, if you feel they're being unnecessarily rough. Maybe they just don't know.