The issue is not whether you are for gun control or not the issue is why a Mayor decides to use valuable school time and ressources to send underage children to a political rally. Imagine a Mayor sending Children to a Trump rally the Democrats would be outraged.
Children know nothing about guns except what they see on tv. They are like leafes in the wind, they will go whivh ever way the wind blows. This is exactly why political actors love to use children.