I would hate to be mechanic just for stories like this.
Look at it from his point of view, a guy calls back two weeks after and says his lug nuts are too tight and caused his bearing to be screwed. If you're a tech, you know that he might as well said my lug nuts are too tight and now the tire is flat. They are related to each other about the same.
So a few days later, after realizing that story doesn't hold water, customer comes up with a new story, of course the shop is going to tell him to pound sand.
Was the axle bearing loose? Maybe. Maybe it was tight and wasn't staked. Maybe. Was the bearing trashed on a 10 year old car? Maybe. Once the customer start taking it apart, it's now the customer's problem.
Sucks for both parties. OP is out a bearing. JDM is getting some bad ink.