I never understood that. Ukraine had one of the largest nuclear arsenals in the world and was also a major arms and aircraft producer. Not to mention they built the Mriya (AN-225), one of the largest aircraft in the world to ever fly. They had their own homegrown cruise missile (Neptun) which took out the Russian cruiser Moskva. They have done a good job of converting older anti-aircraft missiles into ground attack weapons.
The nuclear arsenal was a leftover from the Soviet era. As far as I know no Soviet nuclear weapons were developed or built in Ukraine.
The secret that the Russians don't want to admit is that the Ukrainians were in some ways the technological backbone of the USSR. During the Soviet era about 25% of all scientific research was being done in Ukraine and Ukraine has 17% of all Soviet defense production. The Moskva was built in Ukraine. A sister ship of the Moskva still sits incomplete in the river near Mykolaiv. The Antonov aircraft design bureau was and still is in Kyiv. There was a major tank plant in Kharkhiv.
In the late 1980s the Russian education system fell apart. The last generation of Russians who got a good education are in their 50s now. Ukraine's education system remained in good shape and they have been turning out well educated people since the Soviet era ended.
The ethnic Russians look down on all the other ethnicities in Russia and the former Soviet Union. Being "Russian" has two meanings. Anyone who lives in the Russian empire is Russian, but the better Russians are those who are ethnically Russian. The other Russians are better than non-Russians, but are inferior to ethnic Russians. Unlike the eastern and southern ethnicities who look different, the Ukrainians hold a weird place in the racist hierarchy among the ethnic Russians. On the one hand because Ukrainians look the same as ethnic Russians they are held in higher regard than those who look differently, but they are still primitive barbarians compared to ethnic Russians.
I have seen political cartoons published in Russia from early in the war depicting Ukrainians as primitive tribal people wearing animal skins, living in grass huts and hunting with spears.
Additionally the Russians don't see Ukraine as a real place with a political identity. Like Americans may refer to a region as Southerners or Appalachians. These regions consist of multiple US states, but don't have a separate identity beyond being a region of the country (with their own culture).
The Russians have been working hard for decades to sell the rest of the world on their viewpoint about Ukraine. Early in the war a lot of people referred to Ukraine as "the Ukraine" which is a subtle trick coming from the Russian viewpoint. Referring to Ukraine the country as "the Ukraine" casts Ukraine as just a region of Russia.
Timothy Snyder is a Yale history professor and one of the top experts on Eastern Europe in US academia. He did a course on the making of modern Ukraine last fall and the university posted the entire course to YouTube
He goes into a lot about the cultures of Ukraine and Russia and how the evolved into what they are today. It's a great course, but it is close to 23 hours long.
With sat to sat links, the only thing that would stop starlink working in Russia is jamming
Why does Elon need to play ball with Russia? Tesla has no operations there. Neither does SpaceX
Elon has been befriended by a rather pro-Moscow group of people. They have been influencing his thinking.