Why can you go to the store and buy rubbing alcohol to drink? It’s primary ingredient is just ethanol. The FDA literally mandates that the ethanol is not able to be safely consumed and is cut with poison that is not easily separated from ethanol.
Similarly, cutting opioids with Tylenol is not actually intended to be a deterrent to someone who gets their hands on the pills rather it deters people involved with illicit drug manufacture and distribution from using it as a base to grind up and sell.
Tylenol is really not super safe, at least by todays approval standards. Most official sources, which unsurprisingly have a huge bias towards Tylenol’s safety, state that allergic reactions are very uncommon, but recent meta-analysis’ are beginning to uncover that mild to moderate allergic reactions to acetaminophen is more common that originally thought. It does not get reported because if you’re already feeling like crap when you take it, some mild itchiness, redness, and discomfort would not be out of the ordinary without the Tylenol. As mentioned before, the toxic dose is much too close to the effective dose, I’ve heard from medical professionals that doubling a single recommended dose on extra strength Tylenol is enough to cause long-term damage to your liver. On top of all that, the fact that it is a weak pain reliever at best would solidly put this as a drug that’s not super useful.
I have a very low opinion of how we go about drug policy in the US. I am on a very controlled medication due to a sleep disorder (that causes hypersomnia) which I cannot go off for safety reasons. I also cannot get it filled more than 24 in advance without complicated authorization procedures that must be completed in the correct order. It’s a goddamn mess and serves only as a punishment to law-abiding patients for needing this medication. It also does nothing to curb illicit use because synthesis of a more potent product is so trivial.
This is an example of poorly targeted legislation, which was put into place because it’s the only thing they could exert control over. It does not further the stated goals of drug enforcement because it’s so easy to manufacture this stuff and the resulting product is so easy to move, bad actors can simply avoid this system. While I’m spending 3 hours every month orchestrating the complicated dance of my prescription between my providers, the pharmacy, and my insurance, someone is making a batch of shake-and-bake meth in about 3 minutes.