When Rob Zombie initially went into meetings with Dimension and the Weinsteins about writing and directing a new Halloween film, he had two separate pitches in mind. One was a prequel to Halloween, exploring Michael's childhood and his years spent at Smith's Grove Sanitarium, and the other was a straight remake of the original film.
Ultimately, the studio chose the more bankable idea of just remaking the original. However, during the writing process, Zombie began to experiment with incorporating elements from his prequel pitch into the remake's narrative and resulted in the finished film being a combination of the two. This juxtaposition between the new and the old is a conflict that the film can never really resolve.
Halloween 2007 simultaneously wants to be a completely different beast from the original and a worthy remake. Once it gets to the second half of the film where Michael is an adult, lines, moments, and even entire setpieces from the John Carpenter classic are copied verbatim.
At the very least, Zombie seems to be on cloud nine during the early sequences of young Michael. It is blindingly obvious that that is the film he would have rather made, and he practically said as much on several different occasions during interviews.
Thus, when the film segues into the remake portion of its runtime, it just feels like Zombie is trudging through it because it's what the studio is actually paying him to do. It's a film that wants viewers to be in awe of Michael's radical new origin story while simultaneously expecting them to go nuts over some of the most blatant and in-your-face 'here's a line you know!' fan service ever put to screen.