besides the fact that dragging a sledgehammer into the department of defense is really obvious.

And that hitting something with a sledge or smashing a window would both activate alarms, and just, be really loud regardless.

Yes, there is places without windows and with reinforced doors

Even setting that aside, impressioning attacks require only seconds at a doorway for each step in the process, this defeats that attack.

bump keys only requires ~30 seconds if you are lucky, this defeats that

And yes DoD has security cameras, most places do actually.