Some people argue since the founders had slaves, and times and values have changed, the Second Amendment no longer applies.

Granted this is a seriously malformed argument, but there are people who earnestly posit such a statement. Of course we could preface the beginning of any statement accordingly in an attempt to disregard any of the rights in the Constitution.

Like it or not the Second Amendment is law. The law cannot be ignored because one considers the practices of lawmakers at the time disagreeable or immoral by today's standards. By the same reasoning, if our President or members of Congress commit immoral acts, is the legislation they passed suddenly invalid?

Incidentally slavery and the slave trade were abhorrent to many of the delegates at the Constitutional Convention, even to some from the South. However Southern votes were necessary for ratification, thus slavery was protected in the states where it existed.

Whatever the vices and imperfections of the Founders, they were masters at establishing a republican form of government. This is not saying the government they established was perfect. They gave us mechanisms for changing the laws and Constitution as necessary.