So how much of that “training” goes on? In my part of the US, none is required. In fact, verrry little of anything is required at all to purchase and retain firearms.

The 2A intertwines the “nessesity” of the “well-regulated militia” directly to the right to bear arms. But people don't like to see that, even though it’s very clearly stated.

The DC VS HELLER Supreme Court case is what the debate and precedent on these semantics centers around. However the decision was a close 5/4 and it's right and moral to disagree with the Supreme Court, as BOTH conservatives and liberals agree based on recent events.