“US intelligence has warned that Putin aims to topple Ukraine’s government, round up prominent Ukrainians “to be killed or sent to camps,” and install a puppet regime in Kyiv. When Putin speaks of “de-Nazification” and “bringing [Ukrainians] to justice,” this is exactly what he means.
The word “demilitarization” hints at the real reasons he’s willing to do this: that he wishes to end Ukraine’s status as an independent sovereign state.
Putin believes that Ukraine is an illegitimate country that exists on land that’s historically and rightfully Russian. Zelensky’s willingness to move away from Moscow and toward the West is, in Putin’s mind, an attempt to legitimize the “false” regime in Kyiv. The existence of an anti-Russian regime in what he views as rightfully Russian territory populated by rightfully Russian people is unacceptable to him — so unacceptable that he is willing to wage a costly and bloody war over it.”
…
“talk of “de-Nazification,” while absurd on a factual level, is nonetheless revealing. It tells us that Putin is acting on his long-held belief that the Ukrainian government has no right to be independent. It hints at his ultimate goal: to transform Ukraine into a vassal of a new Russian empire.”
https://www.vox.com/2022/2/24/22948944/putin-ukraine-nazi-russia-speech-declare-war