My family and I have always enjoyed staying at a H...

My family and I have always enjoyed staying at a Hilton hotels. The staff is always friendly and courteous, the rooms are spacious, clean and welcoming. The breakfast is always fresh and delicious. However this stay had a bit of an hiccup in it.
On our last night, late Friday night my husband stop by front desk to ask for water, the front desk clerk was rude with her response. He then walked across to the gift shop and got a bottle of water. When she saw it, her reaction was; "THAT WATER IS EXPENSIVE!". He then said "charge it to the room". She said "THAT WATER IS VERY EXPENSIVE!" his reply "charge it to the room". She said IT'S VERY EXPENSIVE!" he said "how much is the water?" She replied, "$5". He said "CHARGE. IT. TO. THE. ROOM."
What made her think he couldn't afford a bottle of water that cost $5? Our room wasn't free. Our CC on file wasn't declining. So what gave her the impression that he couldn't or shouldn't afford a bottle of water? It's insulting to say the least.
I'm giving a 2 star even though all other staff members were awesome, the encounter with front desk was very disappointing . It takes one bad apple........