National manufacturers have to design toilets for western states where conservation is a huge issue - might just be cheaper to sell those toilets nationwide than to have a different product line for wetter states.
Definitely an odd thing to regulate federally. No reason at all why toilets in New Mexico (average annual rainfall 13") and Mississippi (56") should be held to the same legal limit of water usage.
The low flow restriction was criticized at the time for exactly that but I believe the reason it ended up in the bill is twofold: manufacturers wanted a unified standard at the national level that didn't change at the whims of 50 different state legislatures and the bill was geared towards energy conservation, not water usage. Since toilets account for 30-40% of indoor water usage and pumping water around is quite energy intensive, it does have an effect even if you're in a wet region.
If that is your normal everyday experience you should consider changing your diet and or your toilet. Neither my wife nor I clog a toilet more than about once a year. The double flush might happen once every other month.
I don't think GP is saying he clogs the toilet, but rather that a single flush does not clear it. We have very low-flow toilets, and sometimes my little kids have to double-flush. It's not about diet or anything — the toilets are just very low-flow (assuming you only have to flush once).
National manufacturers have to design toilets for western states where conservation is a huge issue - might just be cheaper to sell those toilets nationwide than to have a different product line for wetter states.