There's a nice takedown of the letter here, though as I noted in an earlier posting, most signatories (happily) are not academic philosophers.  But some are, including the very first signatory (Elise Springer [Wesleyan], who may or may not be the author, I do not know).   (Here's a copy of the letter with the signatories, the original letter site is down.)

Here are the philosophers whose names I recognized who signed this letter along with their institutional affiliation (I'm sure I missed some):  Elise Springer (Wesleyan), Lori Gruen (Wesleyan), Alice MacLachlan (York, Toronto), Tempest Henning (Vanderbilt), Luvell Anderson (Memphis), Gaile Polhaus (Miami University, Ohio), Samanthan Brennan (Western Ontario), Adriel Trott (Wabash), Leigh Johnson (Christian Brothers), Cynthia Willett (Emory), Lisa Guenther (Vanderbilt), Sharyn Clough (Oregon State), Ed Kazarian (Rowan), Cassie Herbert (Georgetown), Nora Berenstain (Tennessee), Rachel McKinnon (Charleston), Naomi Scheman (Minnesota), Rocio Zambrana (Oregon), Perry Zurn (American/Penn), Robin James (UNC-Charlotte), Karen Frost-Arnold (Hobart & William Smith), Julinna Oxley (Coastal Carolina), Daniel Smith (Penn State), Lisa Miracchi (Penn), Mark Lance (Georgetown), Ammon Allred (Toledo), Janice Dowell (Syracuse), Axel Mueller (Northwestern), Jill Gordon (Colby), Lynne Tirrell (U Mass, Boston), Alisa Carse (Georgetown), R.A. Briggs (Stanford),Lori Watson (San Diego), Annaleigh Curtis (PhD, Colorado; currently an attorney), Gabriel Rockhill (Villanova).

As a couple of readers pointed out to me, two signatories–Gruen and Guenther–were actually members of Prof. Tuvel's dissertation committee.  What a thing to do to a former student!

Now some of these signatories are among the "usual suspects" involved in cyber-nonsense (see, e.g., here, or here), but many are substantial and accomplished professional philosophers, junior and senior.  So I ask them:  can you please explain why you signed this letter?  You may also indicate if you now regret having signed, in light of the many criticisms that have been made.   Only signatories to the letter may post here (including signatories not mentioned above, whom I missed).  I will not permit responses to the explanations offered, this comment thread is strictly for those who signed the letter.  Given how outrageous this entire episode seems to so many, I think, in the Millian spirit, we need to hear from those involved as to how they are thinking about this episode.