Those loopholes are how we get people and organizations to do things though. Americans get pissy if you tell us what to do, so unless it's something dire it's better to offer an incentive than to make demands. Tax breaks are an easy incentive to offer.
Let's separate loopholes from incentives. Best example: even though there is "incentive" to stow your wealth in an offshore account, I'd like to call that a loophole. I guess by loopholes, I mean straight up tax evasion. And I'm under the impression that there's a LOT of that going on, but I don't know that anyone has accurately quantified just how much. Anyway, this isn't in the realm of things that I get payed to know, so I'm pretty lacking in concept. Feel free to school me :).
I'll rephrase my campaigning as "anti-tax evasion" and keep loopholes synonymous with incentives. If only we had more taxes to better fund the IRS, so they could crack down on evaders. Self-defeating.