This has nothing to do with liking (or disliking) the swivels. I don't have a strong opinion about them, either.
Obviously, any opinion expressed in one sentence does not allow for nuance.
I fully agree that if you use the right swivel (with appropriate working load limit, corrected for any side loading, properly installed, regularly inspected for corrosion or other failures etc.), and you use it correctly, you should be safe and could sleep soundly at night.
However, there is a number of reports and articles showing that not everybody follows such practices. Practical Sailor (02/2016) questions the need for a swivel in the ground tackle. Adventure Cruising (2010) asks "just to say no" to swivels. Many others, including the article in Sail, warns about problems, if not used correctly. Maine Sails advises to replace them every 2-3 years.
So it seems to me that there are serious issues that many sailors experience with swivels, and because of that one should be quite careful before deciding to install one. There is a serious potential for reducing the strength of the ground tackle. That's it.
(btw. I am sorry if I offended anyone in my previous post; it was not my intention)