Re-washing restaurant styrofoam cups

Okay so. My boyfriends family rewashes the styrofoam cups they get at restaurants. This bugs me so much!!! They have 4 cabinets full of glass and plastic cups yet re wash these bacteria, crusted up drink styrofoam ones. Their idea of "washing" is putting soap in it and running hot water in it for a while. They even re wash the straws. They don't keep up with whose is whose... I think this is so gross and unnecessary. And they're well off financially! His mom was in a bad wreck and all the boys in the house are not cleaning anything. So to help out I cleaned the kitchen today. I threw away about 10+ of them. The dad still had 3 left somewhere else and was like oh man you almost got rid of our collection... My boyfriend obviously has the same "re use everything" mindset and it drives me insane!! 😅😅 what do yall think??