A lot of fans seemed to take issue with Luke's Force projection, but Star Wars used to be a franchise chock-full of wacky magical goings-on. Remember in The Empire Strikes Back, when Luke fights a psychic ghost in a haunted swamp cave?
How are people OK with haunted caves but not astral projection? Plus, from a certain point of view, it's nothing but a variation on the Jedi mind trick, only it fools the senses of everyone. Like a more extreme version of the power we saw in A New Hope, when Obi Wan magically conjures a sound effect to distract two Stormtroopers.
And as director Rian Johnson cheekily pointed out, there is precedent for that particular superpower in the 2011 book The Jedi Path. But then again, that book and all its contents have been tossed out of the Star Wars canon, along with the time Wookiee diarrhea led to the destruction of the Death Star.
Why Doesn't Everyone Employ The "Holdo Maneuver"?
In an act of desperation, Admiral Holdo makes a hyperspace jump with the First Order fleet in her path, wreaking havoc with a lightspeed kamikaze strike. Which raises the question of why people don't do that way more often in this universe. Couldn't the Death Star have been easily taken out by sacrificing, say, Porkins?
Well, beyond the obvious obstacle that most people aren't generally inclined to suicide even on heroic terms, her move doesn't do that much damage. It splits Snoke's ship almost in half, but doesn't destroy it or kill anyone important (Snoke gets cut almost in half by something entirely different). Plus, it cost the Resistance their big fancy spaceship, making it a wildly impractical tactic that only really made sense in that particular situation.
Well, Why Didn't Holdo Tell Poe Her Plan?
He was being a total asshole.
Seriously, watch their conversation again, and look at it from Holdo's perspective. This Poe guy was just demoted for insubordination, and since Holdo's kept in the dark about the First Order's hyperspace tracker, as far as she knows, there's probably a mole on board.