Your premise assumes people are morally consistent, and that’s just not how humans work.

Someone can hold racist or classist views and still feel real anger, empathy, or a sense of justice in a specific situation. People compartmentalize constantly. Having prejudice doesn’t turn off basic emotional responses when something concrete and personal happens.

Also, it’s not true that there’s “nothing in it for them.” There are always underlying factors like personal identity, guilt, attachment, social image, or even just the need to see oneself as not completely awful.

What you’re describing isn’t a contradiction. It’s exactly what real people are like, and why well-written characters behave that way too.