It's not that people skip over it, it's that it's interpreted differently depending upon who you're talking to and/or whose ax is being ground.
The article below goes over a large amount of the differing interpretations and historical contexts of that phrase:
https://reason.com/2019/11/03/what-is-a-well-regulated-milit...
-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
People try to twist it up to mean that only well regulated Militias have the right to keep and bear arms, but it's pretty clear that the Founding Fathers did not mean that in any way. Private citizens owned cannons and freaking war ships back then.
At the time it was written ‘militia’ meant every able bodied adult male, and ‘well regulated’ meant something like ‘suitably prepared’.
There are debates about this, but a simple modern reading of some kind of rule based army is not likely to be what was meant.