Groups wanting to ban firearms and groups wanting to ban books are ideologically the same. Their back and forth petty bannings only encourage the other block to the detriment of actual human persons. Both believe their group ideologies override the rights of the individual and both are willing to use violent force of the state against people.
Trying to apply rational arguments to either "side" (of the coin) is inappropriate since neither come from rational positions. But there are plenty of people against the banning of both. They're just quieter without billion dollar lobbying groups required to achieve their goal of status quo.
But, if we want to be extra clear, legal minors at a public school don't have many civil rights. It's frustrating that they're treated so badly but that's the legal code. Technically it's probably legal to do this (but it should be challenged in court). Whereas adult citizens have far more clearly defined property rights; especially on their own property.
And interestingly there's a strong argument to be made that gun control has already been implemented by the conservatives of a different era to hurt a specific out-group people were conditioned into hating at the time.