It's not like having carve outs makes it any less regressive. It just allows the government to paper over a very complex problem with a naive and simple "solution".

Unfortunately, this sort of thinking has been the dominant mode in politics and legislation since, I dunno, the Roman empire? Riddle your laws and regulations and tax-codes with exemptions and deductions and carve-outs so you can please the people who put you in power and who will keep your in power. And since almost everyone is part of some random interest group (and many, part of a lot interests groups like married home-owning couples with kids), it usually works.