If you go to a high level of abstraction, you remove useful distinctions. That is not a productive line of thought. Not all income is the same, and not all expenses are the same. Excise taxes and any "nudge" tax laws make this obvious.

It is true that there are some tax deductions that are abused. However, the effect of encouraging investment by businesses is much more important.

>If you happen to be the owner of a corp you can also use those things to your individual benefit.

This could be considered an abuse. However, the benefit of encouraging investment by businesses far outweighs the negative of this abuse. We tend to focus our attention on a few big individuals who cheat, and this excessive focus throws off our moral intuitions. Heck, the gas station owner might have deducted the cost of buying a toolbox needed at the workplace, and then borrowed a wrench from that toolbox to go home and fix his plumbing. That would be fine with me, to the extent that all the damn tax paperwork stops being worth keeping track of.