If a user wants to edit or delete any post they've made, past or present, that is their prerogative and no one else's. They should be able to do so freely, regardless of what anybody else thinks, including the admin. It's their post, not yours or anybody else's.
I'm a member of multiple other forums where there is no time limit on editing posts and all those forums still keep chugging away. All of which have been established for a longer period of time than this forum. This post editing lock is just plain unnecessary and in my opinion quite absurd.
You make it seem like if you lifted the editing lock, the whole forum would collapse and be filled with useless threads and missing posts. You can't just control what people do and say.
This is honestly making me not want to continue contributing to this forum anymore. This is too bad, because I've really enjoyed being a member of this community, sharing new parts I've found, posting pics of new mods, and seeing what other members have done to their cars. However, I can't just stand idly by while handcuffs are being put on every single one of our posts for no reason!