ExcitoToxins-- "100%Safe" or "Health hazards"?!

Are "Excitotoxins" safe to 100% of the population who consume or come in contact with them OR do they pose various health hazards?

At this writing, there appears to be two major groupings of these.
#1) MSG based: including a host of pseudo-names that are reputed to ALWAYS contain MSG.
--Glutamic acid, Calcium caseinate, Sodium caseinate, Gelatin, Textured proten, Hydrolyzed protein, Yeast extract, Yeast food, Autolyzed yeast, Yeast nutrient. [And a host of pseudo-names that very OFTEN contain MSG also exists!]

#2) ASPARTIC ACID-ASPARTAME, vs the plant Stevia

I show highly credible website FACTS and INFORMATION from (U.S.A.) Center for Disease Control, CDC Additves in Vaccines FACT SHEET. Two key WORDS stick out: --Formaldehyde...and --Monosodium glutamate (MSG)... is also found in many foods, especially Asian foods and flavor enhancers.

REGARDING this mistatement of fact!
Z) "..The faulty premise behind these allegations {that aspartame is unsafe} is that consuming large amounts of aspartame causes aspartic acid to reach high levels in the blood... "

THE underlying premise IS NOT what the "ExcitoToxin manufactures" argued above as arguement "Z" , BUT an arguement that alledges that:

A) "ExcitoToxins" are chemicals, additives, preservatives or flavor enhancers THAT EXCITE neurotransmitters in the brain to an abnormally high level and thus tend to prematurely burn out or destroy these nerve cells!

B) Long term exposure to these "ExcitoToxins" {where they were not exposed previously etc.} by any population of people in the world is alleged to be the root cause for SIGNIFICANT INCREASES in various nerve/brain related diseases in said population of people!