I did log on to JewishGen but still saw no reply button.  Then I futzed around, officially (re)joining the discussion group and then wandering thru my account demographics and gave up in frustration.  Subsequently went back to a daily summary message and amazingly, there was a reply button!!  Now it shows up every time I click on a subject, regardless whether I'm logged in.   I wish I could reproduce the path for you that brought me success but I can't. 

BUT....just now i brought up the website.  I'm not logged in  Displayed though are 4 login IDs.  I had previously logged in using my researcher #.  There were also 2 old email addresses that forwarded emails to my 3rd currently used address.  With the account activity of a few days ago, i seem to recall adding the new address.  Of the 4 login IDs available to login, that is the only one to show "groups.jewishgen.org".  The older 3 show "from this website".

Maybe that's how i did it.  Just sharing.