OK, now to be accurate, the US does have systems that can shoot it down. However, none of them are actually in the theater.
Now take a good hard look at that "article". Notice what was missing? Go on, take a look and see if anything actually stands out.
What US missile defense systems are there that might intercept it?
Gee when you are talking about missile defense, if you want to sound actually knowledgeable you might want to actually discuss the actual systems that are available. Otherwise, it just comes off as either somebody talking our their arse, propaganda, or both.
Now of the missile defense systems in the theater, that actually is correct. There are none that are capable of intercepting an IRBM. However, as the only real missile defense systems in the region are PATRIOT, and S-300/400, that once again means nothing. The PATRIOT was never intended to be used against an IRBM. And while Russia claims that the S-300/400 can intercept an IRBM, most pretty much dismiss that claim. In fact, the entire S-300/400 reliability and ability has largely been called into question because of the many failures of it on both sides in this conflict.
Then another important question, was there actual air defense assets in place where this missile hit? No nation has any kind of "blanket shield" that can defend everywhere. You place your ADA assets around critical targets, and only engage inbound threats to those targets. If kinda sucks, but if your mission is to defend a military hospital and you see an inbound missile has targeted a civilian housing area nearby, you just have to let it go. Because the civilian housing is not your defended asset.
But what does the US have that can defend against an IRBM? Well, two come to mind immediately.
First off, there is THAAD. But there is no THAAD in theater, so other than the theoretical there is not much reason to discuss it other than IRBMs are indeed within it's capabilities.
Then you have the one system that is in the region but not in the theater that can also take out that missile. And I find it particularly puzzling that myself, a retired Marine and Soldier has to bring up something that a former Naval Officer failed to mention. The AEGIS missile system and the SM-3 missile. The Navy has put a lot more work into missile defense like this than the Army has, because they have ships. And it is easy to throw a 6 million watt RADAR onto a ship, it's kinda impossible to make any mobile RADAR system that is much more powerful than around 500 watts. And when it comes to threats like IRBMs and ICBMs, ultimately the power of the RADAR used to track the threat is of critical importance.
Which is where we reach the strange hybrid that is AEGIS Ashore. Something that Poland and Romania have, which pisses off Russia. In essence, a shore mounted AEGIS system, with the SM-3 missile intended to take out ICBMs and all lesser threats. However, it is not portable at all. But it would not surprise me when this is over if Ukraine elects to but some of those systems as well.
Then finals you have GMD. But no, that one is off the table as it is for use against ICBMs. Sure, it can intercept an IRBM, but that is not their job. Plus where they are located, they could never intercept an IRBM in Europe.