I never heard of any such restriction on Survival journals and have posted numerous modded Survival journals myself, including opening discussing the mods that I use, as have others - after all, modded Survival is still Survival. The mods section is just for discussing mods themselves and I've never seen any Survival journals there.
Here is my most recent journal; a few of the posts (e.g. #16) entirely discuss some aspect of the mod I used, not what I did while playing while many others mention various mechanics and other things as I came across them: http://www.minecraftforum.net/forums/minecraft-java-edition/survival-mode/2780836-themastercavers-world-version-4
Thanks for the response, I may start posting tomorrow then.