Why does Obama keep favoring "small" businesses?

President Obama seems willing to help small businesses that make the investments that he thinks that they should make. But why should the federal government be determining whether small or large businesses get help? If you go from 49 to 50 employees or from 99 to 100 or whatever, what business is it of the federal government? He wants to raise the marginal tax rate for small businesses even while he gives them deductions if they make the investments that he approves of. From Politico's coverage of Obama Saturday radio address:

President Barack Obama used his weekly Saturday address to lay out his agenda for investing in small businesses and curtailing outsourcing while also reiterating the message that Republican policies favor deep-pocketed corporations.

He promoted a slew of policy provisions aimed at increasing investment in small businesses, providing tax breaks for research and development, and tax incentives for clean energy manufacturing. . . .