Cue Morgan Freeman being beaten by a flashlight

I'm not OP, but the Maglite was originally developed for use by American police in the late 1970s. They made it long and heavy so that it could be used as a club (sorry, "impact tool"). Like most things that the police did during that time, these were mostly purchased with the intent of providing plausible deniability about racial profiling and police brutality (and if they weren't purchased with that intent, they were often used for that purpose anyway).

Large maglight-style flashlights like that were often carried by people who weren't permitted to carry a truncheon/nightstick, as a big stick full of D cell batteries is an extremely effective club (until it bends). While the idea that mostly people who owned them used them to beat black people is a bit hyperbolic (for a long time they were just the most reliable flashlight you could get) they definitely were also used as a bludgeon. Mostly that role has now been filled by telescoping batons though, just as effective but much less weight to carry around.

They were very popular among security guards that weren't supposed to be carrying a weapon.

I have an old LED maglite (Maybe 4D? not sure) and I haven't replaced the batteries in probably almost 10 years and every time I come across it in storage I click it on just to see if it still works. Never fails

True, but the light will still be subpar compared to a light designed from the ground up to use leds at least, that's been the case with all the maglite led replacements I've tried

And then get arrested for blinding astronauts on the ISS.

They are so mechanical, I wish they made something more human.