
Julie, it doesn't necessarily follow that you should use it (MSG or
something else for that matter) simply because you are not allergic
to it. For example you might not be allergic to (animal) fats, and
like their taste, yet it doesn't follow that you should be using them
(regularly). MSG might have other bad (or good, I am not up on 
knowledge of MSG) effects on your body in the long run, maybe that's
reason enough not to use it. 

Altho' your example of the ulcer is funny, it isn't an
appropriate comparison at all.