And the reasoning is as follows:
The actually morally necessary step is to establish a no-fly zone above Ukraine, enforced by force with NATO fighter jets and anti-aircraft systems.
People (possibly rightfully) consider that this could lead to a WW3, possibly escalating into the usage of nuclear weapons.
So far so good.
So the bargain we do is basically "Ukraine, we would do everything for you, except for starting WW3, which you hopefully understand!".
Really? Everything? Then quit Russian gas cold turkey! No matter how bad it will be (possibly fairly bad, I admit), it will still be less than WW3, which we bargain is the only thing that we don't want, everything else we would do for Ukraine.
---
Can anybody put this into better words??