TL;DR: "... would mean war with russia and russia is a nuclear power ..."
I have not heard that one before.
Jesus that guy was long winded for what could have been a 8 point bulleted list. I may have missed it but to create a no-fly zone the West would also have to engage Russian air defenses which would mean destroying Russian assets on Russian land which is not only a direct act of war but one of the advantages Ukraine has right now is a lack of drive from Russian soldiers and support from a lot of the Russian people. Once we start killing Russians on Russian soil that would undoubtedly galvanize the country around this war.