Because it mandated that oil and gas companies reduce production by 35%.
Even my children know those Accords contain nothing binding or mandatory.
Why don't you?
The Climate extremists don't seem to make any distinctions between cleaner natural gas and other carbon based energy like crude oil and coal.
Scientists (a.k.a. "Climate Extremists") don't bother to make the distinction because there's only a slight difference in the rate at which consumption of both is poisoning the Planet.
"Crude oil and coal consumption is rapidly poisoning the Planet! Quick! Switch to a slightly slower-acting poison!!"
We can't reduce are Carbon emissions if we force a 35% reduction on the production of natural gas.
Who or what is going to force the U.S. Government (much less President Trump...) to do anything it dioesn't want to do?
Main reason the IGPCC targets aren't binding, was the vain hope that might encourage U.S. participation and co-operation.
We can't encourage natural gas companies to make the significant investment in natural gas wells if they are being told they need to go out of business by 2040.
I think you should do some research into the short-term commercial priorities of executives in the Energy Sector
The better question is, why are countries like Germany failing to meet their climate goals despite signing up the Paris Agreement?
Why is that a better question than why did the U.S. withdraw completely from the Paris Accords?