Both things can be true. The West backed the Euromaidan “color revolution” to dislodge pro-Kremlin Ukrainian leader Yanukovych in 2014, causing him to flee to Moscow in exile. NATO also steadily expanded with accessions of post-Soviet republics, especially on Russia’s periphery in the Baltic region.
But can you blame Ukraine, Central Europe, and the Baltics for wanting to distrust Moscow and seek US support? Can you blame the US for expanding NATO to help these new members have security guarantees and a propserous future? After the Holodomor of the 1930s for Ukraine and brutal treatment across Europe during and after WW2 in the USSR, there are lots of reasons for Europe to distrust Moscow. Plus, Russia has started wars and trampled other nations’ sovereignty all over Eurasia since 2000 to suit its goals, including in Crimea 2014, Georgia 2008, Montenegro 2016 (attempted), and of course its invasion of Ukraine in 2022.
That said, this region of planet earth is complicated and it is appropriate for the US to take a step back after 3 years of all-out war and ask what are the US objectives in Ukraine, is the investment worth it, what are the risks, who else is able to step in/ pony up, and last but not least - what are the opportunity costs including investments domestically.