I don’t see how people are so opposed to the idea that “we should help our children become strong and robust so that they’re not offended by everything”.

Life is a lot easier when you can handle people saying and doing things you don’t like without it breaking you. I’m not saying injustice should be tolerated: Quite the opposite. I’m saying that fighting injustice is easier if you are robust enough withstand it when it’s directed at you.

My impression is that that’s what you mean, in which case I wholly agree.