I suggested that the thread be locked because most of the current "contributions" are votes on a poll nearing its second anniversary, not because of your post.
Opinions are like assholes, everyone has one. That is his opinion as wrong as it may be it is still his opinion. You don't avoid injury by not working a muscle. You avoid injury by making that muscle stronger. Those strong muscles in turn help protect the spine. I don't see why you would not be able to work back up to where you were at and beyond. But if in doubt I would get other professional opinions.