That seems like a foolish ideal that has the end result of you being marginalized, with people who would do harm to you and others gaining control of society. Frankly, it sounds like just another system of control invented by religious leaders.
People who actively do us harm should be swiftly and firmly disabused of the notion that what they're doing will ever be tolerated. Anything less is folly.
Christians who live up to the ideal are willing to have a civil relationship with anyone. That's the point. That's tolerance.
It means you actually know the other person, and you're not making (possibly misinformed) assumptions about them. The next step in the relationship may very well be to 'firmly disabuse them', but it's not the first step.
Getting to know them and convincing them not to do it implies that you will not tolerate their actions, but have wisely decided that a soft touch is likely to get you better results.
If someone tells me they think I’m fundamentally a lesser person than them because of skin color, just because that’s how god made us, that’s not a fruitful base for a good relationship.
I think it comes down to just how tolerant we're willing to be. It's easy to be tolerant when the stakes are low; who cares if someone is doing something somewhere else that makes us uncomfortable? The Christian ideal is to be tolerant of someone who is actively doing us harm.