Having just read the text of the ratifying convention of 1788 on constitution.org, a lot of the debate quoted in this article is no where to be found. There is hardly a mention of slavery in general and no mention of blacks or negros. I think this is another case of someone reading into a discussion what they want to read into it. Regardless, liberals might not like it, but the language in the 2nd Amendment is quite clear.
The right of the people to keep and bear arms shall not be infringed.
It clearly states that it is a right. It also states that it is the people that have the right, not the militia. It also states that the people don't only have the right to keep arms (in their homes), but they also have a right to bear them (carry or hold them). It concludes by adamantly stating that this right shall not be infringed.
Merriam Webster's definition of infringe: to encroach upon in a way that violates law or the rights of another.
Merriam Webster's definition of encroach: to enter by gradual steps or by stealth into the possessions or rights of another
Period