What they don't know won't hurt.
If we can't make the connection between MSG and our health, then its not "hurting" us. So true. Its poor genetics, environmental factors, etc.
The health benefits far outweigh the cost.
You'll hear this about vaccines, conventional non-organic apples; I can't quite evaluate the statement about apples...
If you can't read it, don't eat it.
Some things you can read, like natural flavoring, broth, hydrolyzed vegetable protein (sounds healthy, right?) you shouldn't be eating either (see hidden MSG)
I'd like to add one of my own:
If the ingredient list is too long to read, don't eat it.
The number of ingredients in my pizza at home: probably about 17.
Number of ingredients in Freezer pizza sandwiches? astronomical. Certain chips? It'd floor you. Its pretty much been a proven rule in my recent (two-month-longish) label reading experience that if the ingredient label list is long enough you have to take reading breaks, it has stuff in there you wouldn't want to be eating.
A little dirt won't hurt
Of course nothing's wrong with dirt! (Except for the way we're modernly destroying and poisoning it.) I kind of extend this thinking, though, to my vaccines, pesticides, whatever. Hey, my body's tough! It can take it! I've been rethinking this, and I'm not so sure I want much fluoride, chlorine, mercury, all the crazy stuff we get everyday.
Don't believe everything you hear
People use this to say that MSG is safe! They get information about MSG's harmful effects from NOMSG activists, and conclude with this old adage, remaining in ignorance.