I think most of these are not examples of bad writing at all, but are deliberate attempts at humor. It wouldn't surprise me if it turned out that they were not written by students. Some of the selections are pretty clever, and are examples of good writing, since they successfully achieve their intended result, which is to amuse the reader. We shouldn't confuse these with instances of truly bad writing, which can also amuse the reader, though they aren't supposed to. With the academic term just beginning, I fear I will be seeing too many of the latter.
Yes, Scott, I imagine anyone who teaches is likely to become an expert on bad writing. (My lead-in, by the way, is from an old Guy Marks novelty tune - so it was meant to be funny - both by me and by whoever wrote the song.)