"But as Christians the Bible requires that we be nice to others" or so I've been told. As far as I can tell the bible never uses the word nice a single time. It's speaks of being kind, not nice.

Nice is a veneer such as speaking in a pleasant friendly voice or being reassuring with a smile. Kind is treating others as we would like to be treated. If I was making a terrible life-altering mistake would I want others to tell me the truth or be "nice"? I'd want the truth and in fact I got the truth from some not very "nice" people back in my twenties. It got me off the road to ruin. I'm grateful for it to this day.

Was God "nice" when He destroyed Sodom and Gomorrah? Was Jesus nice when He called the Pharisees vipers? Or overturned the moneychanger's tables?

Don't let the world (which hates Christianity) define our morality for us. They sneer at us and think we are fools but we listen to their definition of what Jesus would want? Read the bible, it plainly describes what God wants and it isn't what the world preaches.