Is it common to try to apply statutes from other states to your own? That sounds wrong otherwise why bother having your own state laws?
No, but it's something that's done. It generally happens when more than one state has potential jurisdiction over the case, but it was filed in a particular one. Every state has laws to decide choice-of-law issues, which are when there's a choice between the laws of two separate states that could apply.
A fairly prominent example, argued by Harmeet Dhillon and her law firm, involved Stephanie Clifford (Stormy Daniels) suing Donald Trump for defamation in the Southern District of New York. It was removed to federal court, ultimately ending up in the Central District of California.
The result was a California court used New York choice-of-law, because the case had been filed there, to decide that the Texas TCPA applied to a case being tried in California (because Clifford was a domiciliary of Texas), and to dismiss the case and award fees to Trump.
So in this case, a California court used the law of two different states to decide a case.
One major difference here is both Texas and California have strong anti-SLAPP laws that would likely have had the same result anyway. Colorado has an anti-SLAPP law, but Minnesota struck its own down as unconstitutional.
Choice-of-law rules are all over the map though. (Note this is different from the choice-of-law provisions in contracts where the parties agree to what law is to be used, which courts usually enforce.)
Here's a quote explaining the principle from a Minnesota law firm:
A Minneapolis, Minnesota business lawyer knows that in conducting a choice of law analysis, first a court must decide if a conflict exists between the states’ laws, second the court must decide if a particular state’s laws can be constitutionally applied, then, The third step requires application of a multifactored test, considers the: (1) predictability of result; (2) maintenance of interstate and international order; (3) simplification of the judicial task; (4) advancement of the forum’s governmental interest; and (5) application of the better rule of law.
It's an introductory paragraph to this case which goes into more detail, and yes, the analysis of this kind of thing is gnarly as hell, so possibly Fischer did get it wrong because I don't remember very in-depth analysis. I'm still not buying it, though.
Just as an extremely brief and inadequate analysis, I think we can agree there is a conflict of laws between the states. Colorado has a SLAPP statute, Minnesota threw their own out as unconstitutional. Then, though, we get to the next issue, which is whether Colorado's law can be constitutionally applied. I think it's similar enough to the one Minnesota threw out that no, it can't.
So we wouldn't even get to the intensely gnarly multifactor balancing test. IMO. Even assuming the appeals court hears it at all, which I don't think it will. If they do it will be because it does at least implicate a constitutional issue, and they might have to decide the choice-of-law issue just to decide not to hear it.