The thing is that this is actually not a vague situation. No one is arguing that parents aren't able to teach their kids right from wrong. The issue is when the parents' values come into conflict with the child's own inherent right to express themselves as one of the protected classes specifically outlined in section 15 of the Charter of Rights and Freedoms. Most topically along sex/gender lines, but also many others.

Thankfully being an asshole is not a protected class so we are free to teach people to not be that.