I do not see why admins think that is necessary.
It is part of the phpBB software, the forum admins have nothing to do with writing the phpBB software.
Some plain logic should explain, but any way:
Some people , like me, as well as others do not want to stay logged in, this is especially important if and when perhaps you are logged in , planning to post but get interrupted and you leave the computer unattended, forgetting to log out, Do you really want to stay logged in even when you are not there ?
I am to tired,and am not going to go into the reasons one might not want to stay logged in, but fortunately we do have the choice/option to decide and select.
Well what idiot sets up a web site that is not secure? That should be forbidden in this day and age.
Why should it be forbidden ? My opinion is that seriously violates free speech and freedom to make our own choices, besides that, just because your browser says it is not secure does not mean it really is not secure. Plus, and even though I am not the person that started this forum, calling the person a idiot, is just plain offensive, it does offend me, I have sever websites on dedicated servers, none use https, ssl certificates, so probably your browser will say they are not secure,but I take security seriously,and you would still say I am a idiot,...the real idiots are the people like you that just assume , since your browser does not say it is not secure,and it does have ssl, or is https, it is secure...so you blindly login or just browse a website that may or may not be secure, see:
https://www.semrush.com/blog/https-a-modern-false-sense-of-security/and there is quite a few other informative sites that say basically the same, it is not just 1 blog,... go figure. You are free to choose if you want to visit a web site based on what your browser says, me, I like to be able to visit a website, without some browser or politician telling me I can or can not view that site, like wise, we like having the freedom to setup and run a website,blog, forum , etc, so we can say or write whatever we want, etc.(free speech) ...nobody should have the right to say we can not do that, for any reason. Go figure, and please start doing your own research before posting,...oh well, guess that is your right as well, this is a public forum,..
I suppose you are right, a insecure website would be foolish, the thing of it is, just because your browser says it is not secure does not mean it is not secure, that little dropdown is triggered when a site does not use https, and has absolutely nothing to do with the real security or lack of on any website,