Weight / Fat loss

some places also suggest drinking ice water, due to not understanding what a kcal actually is, or what maths is.

Maybe because it harder to drink? ....*wait *The water is supposed to be "filling" you up, so surely drinking more is better.

A calorie is the amount of energy required to heat one litre of water by one degree (I think) so perhaps they think warm water somehow contains digestable calories?

I'm going to guess they suggest ice water because it will in fact use energy to heat up the water/keep your stomach warm in spite of the ice cold water. Therefore you will be both hydrated, and give your belly a little workout.