For starters I'm sorry you lost your big post, that's a bummer dude. Now that said, if you're on your desktop here, I need to point a few things out. In Microsoft Edge, hitting the Backspace key when you are not in an active text box will in fact bring you BACK one page. I've just tested this on sites that are not AFN, it's a feature of the browser. On Google Chrome and Edge, if you have a multi-button mouse (with thumb buttons for forward/backward,) those too in fact will bring you back ONE page in both Chrome & Edge.
Our site software saves drafts automatically and stores them for a short but reasonable length of time. A 2 hour post time is pretty epic, again I'm sorry you lost it but that's like writing a small novel. Thread creators should have thread rights to edit their own threads as well (if you don't see it, let me know,) so for future reference, you're able to edit/tweak most of your posts if you created the original thread. Losing a big post is a gamble you'd take on most forum software when you're entering information into a window like that for an extended period of time (and I'm quite familiar with other forum software; ) like others have suggested, long, extensive posts may be better typed out using a word processor.
I removed your multiple mentions of GD (seemed a bit trolling after the 3rd mention; ) again I do apologize you lost your content but I don't see how AFN or even the software is at fault under the circumstance. If you think other forums software is better, by all means you're free to use theirs but spamming their link is not necessary.
You've been offered apologies, solutions, and possible perspectives on what could have happened beyond "just blaming us." Hopefully one of those will satisfy you.