HPC, I like Healings suggestions above for things to say. It makes you look like you are tired of them and they are a bore and are interfering with your work, which they are. Start seeing it like they are intruding in your space and your work not just personally and you will see they have no right and you may feel more like saying something straight like above. Thats 2 of us pointing out locks on stock. Ive worked in a hotel and the fridges and freezers were padlocked (this jogged my memory)

I come across mean people all the time and I let them go very far coz Im a nice person (I think most of time) and then I snap and say something cutting and they shrivel and cry lol. Im not good at handling people in a controlled way because I cant understand why people behave the way they do. I too stick up for others and have been met with quizzical looks and whats it to you because the people that pick on others for very little cant possibly understand why one would stick up for another. These antagonists could be dumb as dough, ask them what their IQ is. They dont sound like they are thoughtful sensitive types. You are unfortunately working with people that are not your type of folk.