From Fact Checks of the Eighth Republican Debate, on the New York Times website:
Senator Marco Rubio said President Obama had played down the threat of the Islamic State, which practices genocide.
Senator Marco Rubio's charge that President Obama has played down the threat of the Islamic State ends up inflating the threat from the group. While it is true that the Islamic State has targeted Christians and Yazidis, there is no evidence that it has carried out genocide against those groups.
— Mark Landler
I was under the impression that no-one's disputing that ISIS is taking Yazidis as sex slaves and forcibly converting them to Islam, which easily qualifies as genocide. The only thing I don't know about is whether ISIS is systematically killing Yazidis and/or a subset of Yazidis (what some people may refer to with genocide).
The New York Times has form for failing to state that a genocide is going on.
Is there no evidence that ISIS has committed genocide against the Yazidis?
Update The New York Times has since issued a correction and updated its statement:
Senator Marco Rubio said President Obama had played down the threat of the Islamic State, which practices "genocide against Christians and Yazidis and others in the region."
Senator Marco Rubio's charge that President Obama has played down the threat of the Islamic State ends up inflating the threat from the group. Several organizations have concluded that the Islamic State targeted Yazidis with a campaign of genocide, but there is no evidence that it so targeted Christians.
Correction: An earlier version of this fact check imprecisely described the Islamic State's record of treatment of religious minorities in areas where it has operated. Several organizations have concluded there is evidence the group carried out a campaign of genocide against the Yazidis, as Mr. Rubio asserted; it was not accurate to say that there is no evidence to support that claim. The statement was made in a Republican presidential debate in January, and the matter was recently brought to The New York Times's attention by several readers.
— Mark Landler