Frustrated

Why is it so normalized to be punished at restaurants for doing something wrong and instead of telling you what you’re doing wrong they just decide to change your schedule the next week?? It’s so frustrating and unfair. I know it’s not just my restaurant it’s happening with one of my best friends too. I made some small stupid mistakes recently but I didn’t even know I was doing anything wrong and instead of my bosses telling me and giving me a warning they got rid of one my days next week!! And i didn’t even find out from my bosses I had to find out from my coworkers ughhh