Thanks for your answer. I was curious about the thought processes.
I want to reiterate that I am only speaking for myself... I deal better in actual events than hypotheticals. I'm also not familiar with the specific exchange you are describing.
I get that in the land of tenure, education and the vast world of ideas freedom of speech should be a strong consideration.
I thought I was being specific enough without giving names, but I left one thing out. The information that that poster would retaliate against union organizing appeared in the one-off's thread, so was not really an exchange in the sense of the series of posts in a thread. So on the one hand, it is potentially an offhand comment, not intended to weigh in on the discussion or influence it. On the other, it is a potentially an under-the-radar effort to normalize illegal behavior. Grey areas.
Later, when I felt prompted enough by a related discussion to bring up the previous comment, the poster denied the statement, but I found it and reposted it. We never heard the argument
for the practice. If there is one, it might be interesting to hear.
Obviously for people who aren't concerned about this issue as I am, this is tedious, but I think it's important. Skip it if you prefer.