When you burn the hydrogen you get pure water back too.
That just goes to show that people will complain about anything instead of applying their brain.
There are plenty of valid objections to hydrogen as a fuel, but water use is a total non issue. Not only does it use so little, but when you get energy back out of the hydrogen, the waste product is water again. It’s literally a renewable cycle.
This is an interesting number. Recently, I saw complaints that green hydrogen is impractical because it would use too much water. But if all the per capita energy use in the US went to electrolysis, it would use about 1% of this water per capita (and, of course, green hydrogen would be only a fraction of total energy use, due to all the preferred direct uses of electrical energy.)