Alright. I thought you meant it morally as well as logically, since you highlighted it in that way.
Logically, they need patriot interceptors. Because they are unable to counter Russian Iskander ballistic missiles and Kalibr Cruise missiles without Patriot for ballistics and (more systems can be used against cruise, but patriot has good range, which is often critical) .
It is a critical interest for Ukraine that patriot incterceptors are not depleted globally, as one example.
A critical component is also the good will of the United States, if it cannot be really had under Trump, they know this well. But If it cannot be had, but there are degrees of relations with the US. Ukraine relies on European states buying weapons from the United States, such as air defence in particular (patriot interceptors, AMRAM, every European weapon with America components too).
While it is hardly in the interests of the US, Trump has shown that he often goes against logic, so could deny (and has threatened with) sales of weapons to European states, if these are resold or donated to Ukraine. See the issue here ?
After this, there is the obvious interest of Ukraine that since this shitty war happened, which no one was in favour of, and certainly not Ukraine (how can they they be interested in Russian oil sales exploding, Russia has saved it’s budget now! and interceptors bound for Ukraine, gone!). But when the war first happened. Then it is clearly in Ukraine’s interest that the US win and that it wins as fast as possible. Strict logic of self-survival dicates this.
Tertiary reason, self defence against Iran as Iran continues to be a component of the Russian War Machine.
Do you see now why it might be in their interest, from a pure logical and unemotional point of view, to provide low-cost anti air defence to absolute everyone that Iran is currently shooting at ? A completely Existential Interest too ? If US loses or this goes on for ages, Russia will afford more armies, and significantly so too. And this at a time when Russia is experiencing, for the first time in the war, a critical shortage of manpower at the front.
So not only has Ukraine the moral reasons to do so, but it is absolutely imperrative for them that this war ends as fast as possible with a US victory, Iranian defence industry is degraded to the point where it cannot truly aid Russia (since the war is ongoing anyway), and that Ukraine gets as many political coins that it exchange into munitions and air defence from the Gulf States, the US and yes, even Israel (they have air defence they don’t use, have refused to donate and even sell, to Ukraine because of their Russian Jews being very pro Putin, and so cynical netanyahu didn’t want to make social waves domestically).
So that is the logic.