The users seem cool enough and most posts I see from them are good additions to my feed.
New York City, Los Angeles, Chicago, San Francisco, San Diego, Seattle, Washington D.C., …
I believe the original reason was that there were people downvoting trans positive content, and this let people be transphobic anonymously. (Conversely, transphobic content can easily be removed by moderators.)
And let’s be honest, despite what reddit people might say, people don’t only downvote bad faith content, they use the downvote as a “disagree” button.
Here it is: https://archive.is/4hPrS