Because restricting your diet unnecessarily is silly, and can make eating healthy a more difficult proposition. For most people without food allergies or sensitivities, it does not make sense to restrict something like gluten for no reason. Rather it is better to choose what you eat based off of what is healthy, provides the nutrients you need, and doesn't have an excessive amount of calories.

Well.., I guess the thing here is to define "Safe to eat" because many of my family members and friends "DO NOT" find it safe to eat.
Including nausea, stomach cramping and diarrhea and sometimes vomiting.

1). Is MSG the same as salt?

No. MSG is made from water, sodium and glutamate. Table salt is made from sodium and chloride.

2). Is MSG safe to eat?

Yes. According to Health Canada, MSG is not a health hazard.

BUT some people may have a sensitivity to MSG. It is the glutamate part of MSG that can produce symptoms such as:

Blurred vision
Tingling and/or burning sensation
Chills and shakes
Feeling of pressure on the face
Headache
Increased heartbeat
Nausea and vomiting
Pain in the face, back, neck or chest

These common symptoms of MSG sensitivity are generally temporary and can appear about 20 minutes after eating MSG and last for about two hours. The symptoms seem to happen faster and are more severe if you eat MSG-containing foods on an empty stomach or drink alcohol at the same time.
http://www.eatrightontario.ca/en/Articles/Food-allergies-intolerances/The-Truth-about-MSG.aspx#.U_wvE4JFcqU

Thank you very much eden for posting this. My son has exhibited some of these symptoms (mildly) and I never made the connection until I saw this. It scared me, but I can work on helping him if this is what he has.

After doing some research as well it looks like there is a link between food allergies and the ticks and twitches associated with Tourettes. There are a number of articles about people who have helped their kids reduce the ticks and twitches significantly by altering their child's diet.