I've heard recommendations for water intake from 2 quarts (an
'average' person) all the way to a full gallon a day (my coach's
minimum when I used to run long distance).

A liter is about a quart, so you're not drinking a ridiculous amount.
I've never heard much fuss about drinking making digestion difficult,
but the body can produce reasonable amounts of acid more or less on
command, and a lot of digestion is going to come from the actual
churning of the stomach as well.

If you're not actually feeling negative effects of drinking lots of
water, don't change your habits.  It's VERY healthy for you,
especially if you're on a diet, when you're going to have toxins from
catabolism of fat floating around in your blood.  It also helps to
prevent the un-pleasant issue of irregularity.

Bottom line, don't give much (read: any) credence to anybody who is
not a medical professional when it comes to YOUR body.  Trust your
habits and the signals your body gives you.  Water is a good thing!

A matter of perspective - Drinking a half liter of water
at a meal should be considered standard not a lot.
It's smaller than the small diet cola served by most
places these days.

Nah, just your perspective on what's a standard amount
and what's a lot at a single setting.  You're doing fine.