I really don't understand the concept of something being illegal in one state and not another.
Its called "jurisdiction".
In democracies, the law is decided by elected representatives.
In different places, people have different values, and therefore different laws.
Is that really so hard to understand?
EG, in Massachusetts guns are evil, but in Texas, they're fun.
If I live in Oregon and I ship spores to California, does Oregon expedite me to California to stand trial?
Good one. That's "extradite".
The answer is that its not illegal to ship spores OUT of Oregon, its illegal to IMPORT them into CA. Whomever in CA ordered them into the State would be the guilty party, and would be subject to criminal charge/arrest/conviction in CA.
In theory, yes, if you were facing criminal charges over this but fled the State of CA if caught you could be extradited back into the State to answer for them. In practice, for what its worth, my understanding is that nobody has ever actually been convicted of importing psilocybe spores into CA. Real risk of importing spores is negligible, though I guess you wouldn't want to be the first one/test case.
This is akin to fact of knowlege. In the great state of Florida, you cannot be convicted of posessing p. cubensis unless you KNOW what it is, making Florida one of the forerunners in the realm of thought crime. In this case certain knowlege is illegal and I can't work that out in my understanding of law and the Constitution.
With due respect, your knowledge of criminal law is poor.
The issue is INTENT, which is a necessary component of most (though not all) crimes in most jurisdictions.
In Florida, they take the quite
reasonable position that if you don't know that the mushrooms you've just picked are psychedelic, you haven't formed criminal intent, and aren't criminally liable. This is a a GOOD THING, because in other states mere possession may be construed as criminal intent and the State may not have to prove that you knew that the mushrooms were illegal.
And that brings up ANOTHER beef, how is posession of a small amount of something legal but a larger amount of that same substance illegal? Pseudoephedrine is legal to posess and purchase in small amounts but you can be convicted of a crime should you happen to have a small stash of this stuff in your house and go out and purchase more.
Its because of potential harm. A few grams of a drug, and the implication is that its for personal use. The State has limited interest in preventing individuals from harming themselves. A few kilograms is far more than any person could be using, and the implication is commercial sale. Now the possessor is potentially harming hundreds of people, and the State has more of an interest in preventing it.
That may or may not be "fair", and you may not agree with it, but I think it at least makes sense.
With pseudoephedrine, its a lot more cut and dry. A few pills are pretty clearly for medical use, where as a few kilograms are pretty clearly for use in manufacturing illegal drugs. There is no "grey line" there, because ordinary allergy sufferers never buy more than a few packs of sudafed at a time. There is no need to, and the law deliberately makes it difficult to do this.