I've always found this a weird comparison. There is no more important use of water than providing food. I love tech and earn my living from it, but the importance of food cannot be overstated.
Saying "if it's edible then it doesn't matter how much water it uses, it's justified" isn't a good position to take.
You could also argue that Amazon data centers are crucial commercial infrastructure that used for a lot of logistics necessary to move food around.
Plus California was/is in a drought for years, that's why people bring up the almonds example.