Pseudoephedrine is only one of the many ingredients that are used to make meth.   Honestly, a rational person cannot believe that taking Sudafed is even remotely like ingesting meth.  Just take a look on the web page below, which details the many poisonous ingredients that meth is made from:

https://www.therecoveryvillage.com/meth-addiction/dangers-methamphetamine-ingredients-made/#gref