The whole sentence is “ It is hard to hate up close, and the FBI could bring people up close.”
1 Answer
It is hard to maintain prejudiced hate, once you get to know the person.
Using a New York Times article for context.
The quote appears in a number of interviews and speeches by (2015 F.B.I Director) James Comey, where he discusses the problems with prejudices in the police force. His view is that a lot of the prejudices, against black Americans, from the police force - can be solved by having the police get closer to the communities they are meant to protect.
The idea is that if you have hateful views of a community, from being ignorant, that these can be solved by getting to know the community better. Being closer to the community (in emotional/relationship distance) helps you to see them as individuals and avoid applying prejudiced stereotypes to them.
I have to apologise for the lack of direct/dictionary references on this, as the phrase is not a widespread idiom - but it's meaning will be relatively clear to native speakers.