If you don't want content unsubscribe it.
That will remove from installed folder and workshop.
There is a proviso.
If you use rfmods content in those rfmods can't be deleted until you uninstall the rfmod.
People seem to forget every server they click on will download a rfmod which will keep all content within installed no matter what you do.
That Lemans pack is a special for a event.
It is up to the creator to add information.
Personally I would steer clear of these.
My packages folder is under 1mb
It has 17 rfmods that I make for various disciplines.
All content is in at least one rfmod.
Which means nothing can be updated unless I want it to be.
Any content unprotected ( no rfmod) is at the whim of steam and workshop.
Having content divided and controlled by rfmods also reduces content lists and filter bloat.
Don't do any unchecking or anything else within rF2 as it must be closed for all changes to take effect including any changes you make to settings won't be saved online. You must start the rfmod for server offline make all your settings changes ( audio whatever) then close rF2 and start server for a example.
My 2 cents, I would start using Mod Manger and MAS2 to control my stuff.