One persons' loophole is someone else's sacred cow. Or incentive for societally desirable behavior (eg charitable contributions)
I don't have kids- so why do parents get deductions. My friends who rent wonder shy I should get an interest deduction on my mortgage. Someone else might say that govt should encourage those things (kids and home ownership).
i was only talking about corporations, but... if all private loopholes were closed, with properly adjusted rates, they might not make any difference and not be missed. i'll have to look into it.