Calling out people like Trump who espoused the birther crap a couple of years ago didn’t help.
Tom fiore

Did you know that the birther movement was actually started by Hillary Clinton supporters? Although there’s no evidence that the Clinton herself ever authorised or supported the accusation, Clinton supporters came up with the strategy and Trump and others ran with it.

You can criticize Trump for claiming that Obama was ineligible to run for president (just as he’d do later with Cruz). However, by calling such statements racist without any real proof of such is an another example of how such racism accusations are counter-productive.