Can schools vaccinate against hatred and extremist ideologies?

I recently received an email from my former professor at Harvard, Fernando Reimers, where he wrote about his feelings regarding the Orlando shootings. He said:

"I don't know about the background of the perpetrator or whether education could have vaccinated him against the sick ideas that led him on his path of hatred. I do think schools everywhere could do much more to prepare children and youth to embrace the beauty that lies in human difference, and to prepare them to challenge extremist ideologies. 

The goal to educate all was first articulated by Comenius as a way to overcome the intolerance and discrimination he had experienced. Much has been achieved in including all children in school inspired by that goal. We have work to do to ensure that teachers and schools indeed advance peace and understanding."

I couldn't agree more. As educators and as parents, we have the power to help our children understand that they must stand for peace and understanding. We can help our children to judge others less and empathize with them more, and we can help them to stand up for peace, tolerance, and diversity.

Here's an extract from a letter  I wrote to my graduating students:

"I have learned that when we skin our knees on the sidewalks of life*, we bleed, whether we’re rich or poor, gay or straight, Jew or Christian, Hindu or Muslim, Black or White, Indian or Chinese. I hope that as you venture into a world where people define themselves by how they are different from others, often with violence and hatred, you will remember our common humanity." 

*Skin our knees on the sidewalks of life is a line from Billy Collins' poem "On Turning Ten"