Everything is very conveniently hidden behind the Moderator Agreement. I Understand that there are Privacy Issues, especially In cases where there is use of abusive language.
While precise details of the Suspension need not be disclosed, I think even a line offering the basic reason is necessary so that the community can know exactly why, Such as "Use of abusive language" or "Intentional and repeated spamming" or "Unfounded Allegations against Moderators" or whatever the reason is.
There is another post Which asks for a lot more to be disclosed. But I only ask for a one line reason available to the Public, Especially if you are Imposing 6 Month - 1 Year suspensions to users who are otherwise friendly atleast to me.