It’s pretty simple.
They have an agenda they want to implement and honest, law abiding and peaceful citizens owning guns is contrary to, and conflicts with that agenda.
Even simpler than that, this is class warfare by progressives against those “who just aren’t our kind of people”.
You know, bitter clingers. Or those whose house & kids are off limits to your kids “because they own guns”.
In other words, a bunch of condescending arrogant snobs who unfortunately form today’s ruling elite in America.