The "oh the criminals will do it regardless of a laws" is a hyperbole of no persuasive value.
We don't organize and socialize ourselves by what criminals do.
We enact laws fully expecting criminals to violate them and law abiding people to abide by them. And we don't refrain from enacting laws because criminals will violate them.
So then, why enact laws that serve no other purpose other than making it more difficult for the law abiding citizen to protect themselves from the criminals?
The Second Amendment, "A well regulated militia being necessary to the security of a free State, the right of the People to keep and bear arms shall not be infringed," does not GRANT the right to keep and bear arms. It assumes the people already have that right and only promises to PROTECT that right.
The BAD GUYS are going to have guns no matter what the law says. They don't care about the law. That's why they're the BAD GUYS. It stands to reason (and could be reasonably inferred by the 2nd A, depending on your interpretation of what a "militia" is and what "the security of a free State" is) that the more GOOD GUYS that have guns, which the BAD GUYS will recognize as fact, the less likely they are to practice their vocation of BAD GUYness.
You also have to remember who wrote the second amendment, ratified it, and what they had accomplished. They 2nd amendment was written by a group of men who had just completed the violent overthrow of an oppressive government. Even US Military enlisted persons take an oath to support and defend the Constitution against ALL enemies, foreign and DOMESTIC. The "well regulated militia" was and is the law abiding citizens of the "free state". The right to keep and bear arms by those law abiding citizens is not only necessary for their protection against criminals - it is also necessary for protection against their own government "necessary to the protection of a free state", should such need arise to overthrow that government. Our Declaration of Independence states that it is OUR (the Law Abiding Citizens') duty to ensure that the government that serves us does not become tyrannical.
One of the purposes of government disarming or regulating the possession of arms by the law abiding citizen is to ensure that they do not possess the means to rise up against the government. I mean, after all, we wouldn't a repeat of the Revolutionary War, now... would we?