That would imply that a galaxy, for instance, can move faster than the speed of the expansion of the Universe. Would that not violate a few laws?
Did anyone claim that we understand the makeup of the Universe very well, just well, or passably good?
Well, yes. Every day scientists proclaim some new discovery or theory that they assure is is the absolute truth.
As far as I know, very little is known about the Universe.
Then you know far more than most people.
The criteria of declaring your knowledge to be of the "very well" grade is when you can make your own little Universes, even if they are not perfect.
It's all in our heads.
That would imply that a galaxy, for instance, can move faster than the speed of the expansion of the Universe. Would that not violate a few laws?
Certainly not. First of all, it is possible for some objects to move faster (or slower) than the average speed of expansion of the Universe. But that is not necessary. Even if we assume that no object can move faster than the wavefront of the expansion, there is no law against moving slower. All you need for a collision is a difference in speeds.
You can achieve such a slowdown, for example, in a gravitational interaction of two galaxies. Even a small attraction would be enough to change the course, and that will result in the "forward" vector getting shorter and the "sideways" vector getting longer - leading to lateral movement of the galaxy, putting it into the path of another galaxy.
Every day scientists proclaim some new discovery or theory that they assure is is the absolute truth.
Those are not the scientists you are looking for :-)