1. Most corporations are not "owned by rich people" but are, in fact, owned by shareholders.
Who are, by and large, rich people. The argument still stands, rich people who are making money, are doing so through their own business ventures, in other words, business is how they are earning a personal income in the first place.
Tax the rich, you won't harm business, is as ridiculous as tax the business, you won't harm the rich! Neither of them work in logic, because business and rich people are joined inseparably at the hip. You want to maintain some illusion of separation, as if rich people have nothing to do with business, and that just isn't the case, they are the ones behind the business, by and large, and when you effect their income, you effect their business.
Very few poor people run a business...
Some middle class can manage to run a small business...
Most business in America is run by rich people.
Whether it's a corporation, run by a whole lot of rich people, or a company owned by a rich person, or their family, most all business is run by wealthy people. Thus, most wealthy people derive their incomes from business they are involved in.