As per https://nida.nih.gov/publications/drugfacts/over-counter-med..., "Over-the-counter (OTC) medicines are those that can be sold directly to people without a prescription.". Sudafed—the real Sudafed—is still OTC, by that definition.
Not an ingredient -- a precursor. Methamphetamine, pseudoephedrine and and phenylephrine are very closely related:
https://cen.acs.org/content/dam/cen/83/13/8313govpol1imgs.gi...
To convert pseudoephedrine to meth you have to remove a hydroxyl (-OH) group in a way that leaves the resulting molecule in a specific isomer. Doing this at high yield is challenging, but it turns out that if you're willing to live with lots of horrible impurities, you can do it in a cola bottle.
The Sudafed behind the counter actually works (really really well), but due to what you've described, you need to present ID and affirm that you'll abide by certain federal laws. Oh, and there's a low hard limit on how much you can buy at a time, which is fine if it's just you in your household but not so fine if absurd levels of congestion run in the family and you all live together.
But you will have to go to a shady place since they only decriminalized them...
If it seems stupid it's because it is.