I have lots of respect for anyone who responsibly runs a forum of any size but especially one for exJWs - you have no idea of the constant shit that has to be dealt with, usually caused by a small number of determined and disturbed people who just want to cause trouble. It's easy to just throw up a site and allow "anything goes" which typically ends in it being a tool for harassment, much harder to keep control and make the tough decisions to stand up to people which then makes you their target instead.
So respect for everyone involved for doing so much for so long. I don't think you can ever be critical when people decide they have had enough and want to spend their time and energy on other things - it does often become draining.
Once you get to a certain size you also become a target for spammers and all the general issues of running a large website including hosting costs, securing people's data etc...
So while I can understand some people's disappointment and feeling let down because of a sudden closure you may not be fully aware of all the reasons for it, I think you should look beyond the personal impact and consider the impact on those people and their families. Thanks them for what they provided to you for so long and appreciate the hard work and dedication put toward providing the site they did. If you miss it, then they obviously did a worthwhile job.