You can keep saying this, but Zimmerman has a civil rights claim against the State for depriving him of liberty (and property) without due process, and its actions do indeed undermine his presumption of innocence. This is notwithstanding its stated reason that it is acting because a "controversy" has placed its students in danger, which is clearly nonsense. No students are endangered by Zimmerman's presence at the school. If the State is genuinely concerned that students will inflict violence on Zimmerman, it cannot punish Zimmerman for that reason. Do you see nothing wrong with the State punishing somebody because of the belief that others will violate the law and commit violence against that person?
I think I may have been explaining myself poorly: My main objection is to the idea that kicking him out of school due to 'the controversy' in any way impacts the eventual trial and undermines his presumed innocence in the shooting. Had the school released a statement saying they kicked him out for being a murderer, I'd see the connection. Here they reference something else, the very real controversy, as well as safety in general (and they're not indicating Zimmerman himself is the threat to safety, but the circumstances surrounding him, so they're not pulling the safety card because they're presuming him a murderer.)
My guess is that he wasn't officially kicked due to a non-explanation like controversy, but due to the end result: He's been 'in hiding' for an extended period of time, which likely means he hasn't been attending classes. Their own policy allows for an instructor to withdraw the student, without warning, from any class once more than 10% of sessions have been missed (
here) Once withdrawn for attendance-related reasons, students cannot appeal for re-entry into the course. If he's been out since the shooting, he's over the 10% threshold in all his classes and so would be withdrawn from all of them. If you're withdrawn from all classes, you're withdrawn from the college. I'm guessing it's not something they actually act on frequently, but they certainly appear to be within their stated policies to remove him from his courses.
The safety/controversy angle comes into play as the reasoning behind the non-attendance, and how you explain it to the press (vs 'He stopped showing up for class'.) Him showing up wouldn't be a particularly great environment for anyone, and they're not going to encourage him back. The attendance should give them due process to kick him in the paperwork, at no point presuming him guilty of a crime.