Fundamentally, "parental rights" is a dog whistle about limiting children's rights, usually in contravention of Charter Rights.
Our youth in schools have a right to not be discriminated against based on their sexual orientation or gender identity. SOGI curriculum is based on anti-bullying, pro-inclusiveness principles, to make schools safe and accepting places for all, including gender and sexual minorities. (The same thing can be said about anti-racist education, regarding racial minorities.)
That's it. There's no "hidden agenda" to groom or sexualize children. No teachers anywhere are pushing children toward having non-cis gender identity or non-hetero sexuality. And nobody is showing porn in classrooms.
The lies and gross misrepresentation of what's happening in schools is fueled by conservative politicians manufacturing wedge socially conservative issues to get voters who will ignore their economic policies.
We must have no tolerance for intolerance.