I'm not very concerned about this retconning canon either. Stargate Origins can't possibly contradict SG-1 more than the original Movie ever did. Abydos being in another Galaxy, the Asgard-esque previous Ra host... Stargate never was a shining example of decent continuity in the first place.
Well, that's not at all fair, since it's actually quite normal for TV adaptations of movies to be in slightly different continuities than their source material, because they have to change things to make them work better for the series format. The series based on the Jeff Bridges/Karen Allen movie
Starman retconned the events of the movie from the '80s to the '70s so that the title character could have a teenage son in the present day.
Alien Nation simplified the alien makeup from the movie (the movie aliens had prosthetics altering their body shape, but the TV aliens just had head prosthetics) and ignored a key story point from the film. The
Buffy the Vampire Slayer series made Buffy younger than she was in the movie, changed the portrayal her parents and her mentor Merrick, changed the vampires' appearance and powers, etc. The '70s
Planet of the Apes TV series implied that events similar to the original two fims had happened in the past, but used an earlier calendar date than those films and featured humans who were still verbal and civilized rather than the mute animals of the films. The animated
Men in Black: The Series entirely ignored K's retirement at the end of the movie.
The Real Ghostbusters retconned the movie into an in-universe work of fiction
based on their real adventures. And so on. TV series based on movies usually have to be treated as alternate continuities to the movies themselves. Indeed, SG-1 made this implicit, because they established that the series takes place in a multiverse with numerous alternate-reality versions of themselves out there. So if you're going to judge the continuity of a TV series based on a movie, it's generally best if you
don't count the original movie as part of it, because it usually isn't, at least not in the exact same form.
And the
Stargate TV franchise, disregarding the vastly inferior movie, actually had a much tighter and more internally consistent continuity than a lot of other SFTV franchises, including
Star Trek. It was very good at picking up threads from former episodes and following through on their consequences or expanding them into bigger stories. One of my favorite things about it was how effectively it created the sense of taking place in a rich, complex, and consistent universe. Of course it had a few inconsistencies and dropped threads along the way, as any long-running series inevitably will, but it had fewer than Trek,
Doctor Who, or other expansive franchises.