PARSHAS KI SEITZEI

“Because they did not greet you with bread and with water… and because they hired Bilaam son of Be’or against you.” (Devarim 23:5) 

The Ohr HaChaim asks: Once Amon and Moav hired Bilaam to curse them isn’t it insignificant that they also didn’t greet them with bread and water? 

To add to this question many commentators say that Amon and Moav did sell Bnei Yisrael bread and water but merely didn’t greet them. 

Is the lack of extending a greeting so grave that it’s of the same severity as hiring Bilaam to destroy the entire nation? (Rav Y. P. Goldwasser Be’eros Yitzchak)