The key distinction here is between wealth and income. Most angel investors are funding startups from their existing wealth(i.e. funds from a previous exit) rather than income. And any income they do get is probably taxed at the capital gains rate. As far as I know, Obama wants to raise taxes on income, not wealth.
I love how he says, "Obama wants to significantly raise taxes". Hardly. This seems to be a new version of the same old "We can't tax the job creators." argument.