Why do liberals want to infringe upon my right to bear Arms?

Because you're not in the militia, and what you're describing does not sound "well regulated". The well regulated militia, at the time the Constitution was drafted, referred to the Minutemen. The armed townships that fought the guerrilla war to fight off the British. Now that the USA has the world's biggest military, the "militia" is obsolete. Of course, the Constitution is open to interpretation. Liberals think the "well regulated militia" is our military. Conservatives think it means they should be forming their own little militias to fight against the US army, which is ridiculous I think, but you have a right to your opinion, as we do ours.