Agree with all of the above.
People get anxious about TAs but not Adjuncts. The % faculty who are hired on an irregular basis (typically by the semester) has increased from ~25% in the 1970s to ~40% in 2011 to ~75% now. They may be perfectly good teachers! but they have no job security, and typically have to cobble together enough jobs to pay the rent, often at more than one institution. Even very highly rated teachers can be there one term, gone the next and back the following term.
And, people tend to assume that TAs are more of a problem at big unis than fancy tippy tops- but it was Harvard students who protested at the standard of English of their TAs!