They can, but that hurts if you make any real revenue. If I invest $100 in a business, it spends the $100 but makes $60 as revenue, then the $40 is a loss. (And can be offset by profits in future years)

With this new clause, the calculation will be: income = $100 (investment) + $60 (revenue) = $160. Expenses = $100, profit = $60, and you'll pay tax.

It's like taking a loan from the bank and being taxed on the money as income. You still have to pay the whole thing back! (Effectively, any equity investment is a "liability" on the books; any investor will demand return on his whole investment, not just the portion that wasn't paid as tax)