Oh, well, only explanation I can come up with that makes some sense is that using a receiving platform extends range and that the station was too far from the drydock to transport on its own. And obviously the enterprise crew thought their transporter was fixed at that point.
I favour distortions caused by active warp engines. This means beaming onto damaged ships with no power still works. Beaming onto Enemy ships even with shields down doesn't. It covers transporter warfare up to a point, since you can still beam anti-matter mines outside ships. In fact cloaked ships beaming mines seems like a sensible Romulan tactic.
At the end of the day it's probably one of those things that just don't make a lot of sense. Any explanation in story can probably be contradicted by another at some point. My guess is they really didn't think about it being an issue. They wanted it for dramatic effect and to demonstrate the refit
Enterprise is not fully operational yet but is being rushed out due to an emergency. But it kind of falls flat because after the ship sets off the transporters are never used again in the movie.
And honestly it's my 2nd point that bothers me even more. That no one bothered to tell Sonak and Ciana that the transporter on the
Enterprise was not up to snuff. I can't believe no one called the ship, even just to tell them 2 people were ready to beam aboard. Somebody really dropped the ball there.
When I first got into Star Trek it was the movies first. So when I first saw TMP I didn't think about the 1st complaint yet--needing a receiving pad to transport. It was my 2nd point that immediately came to mind. "Didn't anyone bother to call the ship to see if it was safe to transport?

Kirk knew he couldn't transport, didn't those two?" As much as I love TMP it's one thing that to this day bugs me. Maybe later I'll check my novelization to see if there's any explanation for that, or whether that was even considered. As I've noted before I am an avid novel reader and I can't recall if that was ever rectified in some novel that takes place later. Something else, maybe later, I'll hunt around for because it's bugging me now. Sometimes one of the books explains something away that at least 'sounds' plausible.
And that's fine. I have never treated Star Trek as hard science fiction, so TMP stands out against TOS.
I would say Star Trek is halfway there. It's not 2001: A Space Odyssey level sci-fi. But I remember reading "The Making of Star Trek" which was a book about the making of the show that came out in 1968. Hard sci-fi was at the basis of their thinking, and the set designers over the years have gone to great lengths to keep a level of realism in the sets. They just don't put a plasma conduit somewhere to look cool. They actually think about what that conduit is for in the ship.
But they did take some liberties for dramatic effect. For instance, hearing ships and explosions in space. Obviously it'd be a lot less dramatic to just see the
Enterprise battle the
Scimitar in Nemesis and not hear it, or not to hear the phasers in TWOK. I would say Star Trek took liberties, but the science part of the science fiction was always there lurking around. It never went as far as Star Wars, whom George Lucas has always said was not sci-fi, but a space opera, or fantasy.
TMP was as close to 2001 level sci-fi Star Trek ever got probably. Perhaps that's why it's my favorite Star Trek film. It's closest to real, hard sci-fi Star Trek ever got. Other movies and shows had varying levels of hard sci-fi. Some more, some less. But from a sci-fi perspective, TMP is as closed to the pinnacle they got.