I've always believed cursing people is forbidden in Judaism, but I recently read the following on the Gemara:
והא רבי יהושע בן לוי לייט אמאן דגני אפרקיד
For lo, R. Joshua b. Levi cursed anyone who slept lying on his back!
This kind of shocked me, how could a rabbi of such greatness curse fellow Jews for just sleeping on their back? I wanted to know if there were other cases of curses made by rabbis in the Gemara so I searched for the word "לייט" in Sefaria.org. I was baffled when I realized there were dozens, even maybe hundreds, of this cases. Here are some others;
דהא רב חסדא לייט אמאן דמהדר אמיא בעידן צלותא והני מילי לק"ש אבל לתפלה מהדר
And lo, Rab Hisda cursed anyone who went about in search of water at the time of prayer. This, however, applies only to the reading of the Shema', but for the Tefillah one may go for water.
לייט עלה אביי אמאן דמצלי הביננו
Abbai cursed him who says the prayer "Give us understanding."
How can Rabbis curse other Jews? Isn't this forbidden?