Because that's not how the Force worked in ANH.
In ANH, it was a very different thing. It was subtle, almost like telepathy, and that was it. It was just focused feelings and energy.
Obi Wan used it to confuse the Tuskens and Stormtroopers on Tattooine and the Death Star, and he felt the deaths on Alderaan.
Vader sensed Obi Wan's presence and he sensed Luke's connection to the Force. He "choked" the mouthy Imperial but that could be considered to be the same sense of "strong suggestion" as the Jedi mind trick. He wasn't "physically" choking him but rather making him think he wasn't able to breath. Remember, when he REALLY choked a guy to death on the Tantive IV, he did it with his hands.
Luke's Force abilities were seen twice....he was able to sense where the remote was gonna shoot and he deflected the shots, and of course he calmed himself, focused, and made the shot that blew up the Death Star.
Really, the Force is a much less mystical thing in ANH. It's almost like "mindfulness" or ESP or something.
It wasn't until the writing of ESB that it took on its elevated status as an ability to manipulate physical objects like telekinesis. The first thing we see move by the power of the Force is Luke's saber when he's hanging upside down. Pretty crazy when you think about it. How the hell did he do that? He shouldn't have even thought it was possible.
We again see Vader choking several subordinates but we don't see him moving stuff around til he throw boxes at Luke. And of course there's the levitating rocks and X-Wing on Dagobah.
I don't think it was too outlandish in ROTJ either, with the exception of the Emperor's Force lightning.
And then came the good old PT, which made the Force a full blown super power with crazy running and all that stuff. And Midichlorians. Ugh. At the time I thought I'd never roll my eyes as hard at anything SW related more than the concept of "Midichlorians."
But never make assumptions. Disney managed to reach unthought of levels of full blown stupidity when they introduced a little character called "Rey" who not only possessed ALLLL of the crazy super powers from before without ever being told about them and zero training, but she was also able to PULL A MOVING STARSHIP FROM IT'S ACTUAL LIFTOFF BEFORE OBLITERATING IT WITH HER MIND. Holy crap that is the most blitheringly stupid thing I can imagine.
But that's Disney Trilogy, and that doesn't exist to me, so whatever.
The only Disney that exists to me is Mandalorian, and I don't think Luke did anything in his appearance that would be out of the ordinary in ESB/ROTJ with more focus and training, so that's cool.
Oh....wait.. I forgot.....Grogu "Force heals."
Never mind.
As you can see, attempting make any kind of sense out of this non-stop retconning and reversals going all the way back to 1977 is a complete exercise in futility.
Either accept it all in its complete ridiculousness, pick and choose what you like, or just wash your hands of the entire thing and watch something else.
