Oh God, the next thing you mentioned reminds me of my dad’s family(my phupo, chachi family, etc)…Whenever they used to visit, they used to criticize my mom on every little thing she did in the kitchen. Them and their 2 dozen daughters would gather around in kitchen and talk about how my mom didn’t know how to cook food properly. My mom is an amazing cook but her cooking style is more Pakistani and they are Indians so ofcourse it’s different but NO they will still criticize her. 
I think it’s a given that guests should appreciate the efforts of the host family. Some people are just ungrateful and I agree that we shouldn’t take such treatments from them.