Being a bigot has very little to do with being “nice” or “not nice”. It has to do with who you see as human.
The number of people I’ve had say to me “They’re very nice, just a bit misguided about X.”
You mean they’re very nice to you. A person who fits their definition of “fully human and deserving of human rights and dignity.”
These are people who look themselves in the mirror in the morning and think "I'm a good person." Then they go out into the world and spend the day intentionally discriminating against minorities and then congratulate themselves at the end of the day for "being kind" and "doing good work."
And for them there's no disconnect because they have absolutely been kind to everyone who qualifies in their mind as a person.