Why don't we fuse hydrogen and oxygen to make water

I hear how much water is needed in 3rd world countries so logic dictates that we need to MAKE Aqua(latin for water).

Its not so hard just throw some oxygen and some hydrogen and ta-da! Water.

Okay seriously, sure it would be very dangerous to make water. The possibility of something going terribly and an immense reaction could happend theoretically burning down whatever facility the reaction is taking place in.
Let us not forget many years ago people were worried that internal combustion engine would be to dangerous to use. But we know how that turned out.

We don't have access to enough hydrogen. Hydrogen is the most abundant element in the universe, but almost all of it is bonded with other things. The only reliable source of hydrogen we have is electrolysis of water. This means passing a lot of electricity though water to separate the hydrogen from the oxygen. Obviously, we can't make any more water by doing this because we'd have to use up water first. It would also waste a huge amount of energy.

It's not true, however, that joining hydrogen to oxygen would take too much energy. The two are joined by burning hydrogen. Obviously, this is exothermic and gives out energy. (Not as much as electrolysis of water takes though, as some energy is wasted at each stage.)

Hydrogen is not part of our atmosphere. You would have to produce the hydrogen gas and then ignite it.