In the context of that amendment well regulated did actually mean something more like well trained. The expectation was that owning a firearm would require regular training to maintain proficiency. The 2nd amendment also gave the right to form militias and those have to have some level of "control by rule" etc. by somebody being in charge. No military unit, even a militia, can operate well as a total anarchy. That also is something that would require regular training to ensure the members of the militia could operate smoothly and efficiently.
You might want to post a couple more definitions of regulate and perhaps even read the US constitution and various other writings by the authors that in some cases expounded upon topics included in the document.......