No. You are wrong.
Both PG and VG (glycerin in general) are approved for innumerable uses in cosmetics, foods, and drugs. As for FDA approval for use in pharmaceutical products, both are approved for the following applications, in concentrations ranging from 1% all the way to 98.09%:
Buccal
Aurricular
Transdermal Patch
Topical (Aerosol, Cream, Emulsion, Gel, Lotion, Ointment and Film)
IM and IV injection
Opthalmic
Oral (Solution, Suspension, and Tablet)
Dental (Paste and Solution)
Inhalation
Nasal
Rectal
Subcutaneous
Vaginal
You can see this yourself, by searching the FDA's inactive ingredients database, created for this purpose:
"The Inactive Ingredients Database provides information on inactive ingredients present in FDA-approved drug products. This information can be used by industry as an aid in developing drug products. For new drug development purposes, once an inactive ingredient has appeared in an approved drug product for a particular route of administration, the inactive ingredient is not considered new and may require a less extensive review the next time it is included in a new drug product. For example, if a particular inactive ingredient has been approved in a certain dosage form at a certain potency, a sponsor could consider it safe for use in a similar manner for a similar type of product."
Inactive Ingredient Search for Approved Drug Products: Frequently Asked Questions
To do this search, go here:
Inactive Ingredients in FDA Approved Drugs
Then all you do is put either "propylene glycol" or "glycerin" in the search box on the above-linked to page, and you will see the very long list of approved administrations enjoyed by both substances, and the range of concentrations.