Why should it?
Federal property on Confederate ground is "off sides"
Is Federal property on Cuban ground "off sides"? Does Castro have the right to bombard Guantanamo Bay into surrender?
"Why should it? "
It was on soil that was claiming to be sovereign. The tie was broken. The further existance of such a Fort was an afront to the entire process. A stroke of arrogance if you will (Hell, even if you won't)
And Castro has every right to try to fight us off his island if he thinks he can win. (Also, Castro didn't LEAVE the US, he PISSED OFF the US.)
It just so happens, Castro knows when he's outmatched.