First there is no way that cop was there for 25 years. The number of people that drive down there Canada in huge RVs is a bit hard to miss. The Number of Mexicans that drive up to work legaly is even larger. His boss will have known that even if he din't.
He cant take your bike away he can only impound it the Court can but be he cant.
He works for the state of Arizona (or a county or city) not the USA and cant speak of all the US import laws. Driving laws in the USA are state by state there is no ban on foreign bikes. There is no such thing as a USA plate there state plates.
$600 fine for illegal import, driving a non street legal bike and doing all this across state lines is dam cheap. And a case for the FBI he oversteped his position.

That sums him up bout right

Dam man you got case agenst the city of Yuma and the state Arizona! $$$$$$ You just paid for your trip what with all the mental anguish you now have and damage to bike (you now need a new one) from falling off it after he maid you so jumpy of other cops. God bless the USA and its legal system!

Please tell me you got his name. He is an ass and a clear example of the stupid ugly American sory you had to run in to him.

On the other hand people that are in the USA illegally are braking the law its what the word is. To be legal they need paper work not that hard to get. Much harder to get paper work for a US citizen to live and work in Mexico than for a Mexican citizen live and work in the USA. Id like to be rid of silly paperwork my self, its gust the USA wants it tax $ from even the poorest people
As far as history who has the right to claim what go back before 1700 Norway had people here before Spain and there was Indians (First Nation) before that. Its the Europeans that seem to think only there laws history and people mater. Seems many in the USA take it to the extream.