probably because if you take advantage of a corporate tax break you've already created a company and spent money/paid other taxes. Plus, you're paying less money to the government, not taking some from the government.
Because there are so many people who really do just mooch off benefits. They don't work hard because they know at the end of the day, they are going to get help from the government. Why should I have to pay for their food off my hard earned income?