Earlier quoted context omitted.
There's a line between dumb speech and libel. The faculty members were informed of the facts of the case, yet continued their counterfactual accusations of the bakery, and used the college to put severe economic pressure on the bakery. If that doesn't qualify as libel, what does ? That it was done as part of a protest is orthogonal.
I'm going based on OPs description, which nobody on either side of the debate seems to object to. A different list of facts could convince me of something different, certainly. What were the libelous comments by the college, specifically? I looked at the link provided and didn't see any actual comments from the flyer or dean of student's speech.
Maybe you have some intellectual humility and give deference to the judge and jury that heard all the facts rather than declaring them to be wrong based on a summary of a summary.