If it helps stop the making of illegal drugs, then good.
How much legally would a legit citizen need anyway?
This seems clearly targeted at libertarians or others who want to practice the making of illegal drugs, right?
Glue and spray cans are locked up these days because of abuse as well. The world hasn't ended there either.
Granted you don't need it in huge quantities, but it's a legal substance that some found a way to use in an illegal fashion, so all are looked at as potential criminals when purchasing it. It's a pain to have to wait in line at the pharmacy counter for an OTC decongestant, and to top it off, they want your driver license so they can keep tabs on how much you buy. This is just one more baby step towards controlling everything about us. Next thing you know, we will have to register steak knives and wait three days for a background check before we can pick them up.
If your solution to the meth problem is more government intervention in private industry through locking up the ingredients and limiting their sale instead of locking up the lawbreakers, it is to be devoutly hoped nobody starts huffing gas.