One logic goes something like this. You have to put yourself in a long-term, America-first, somewhat isolationist mindset.
--Start early. Europe has been starting wars with itself for centuries. After the US was created, it followed a strongly isolationist policy. Not getting sucked into European war of the week was a normal American value and not exceptional. The US wanted to take its ball, go home to our hemisphere, and be left alone. Forget Russia and Ukraine, back then it was let France and England keep killing each other for all we cared. The US joined the world wars reluctantly and lately, this benefitted the US from being the least destroyed of everyone; we would have benefited even more if we had not fought at all and not been destroyed at all.
--NATO was created as a post-WWII military alliance against...mainly Russia, but specifically the Soviet Union. When the Soviet Union was a power threat, the US supporting NATO made sense for the US. Since the Soviet Union fell, there is no further benefit for US to support NATO anymore, and it should have withdrawn from NATO shortly thereafter, but there was always the threat of a new communist threat popping up. Existence of NATO at this point is merely a way to foment aggression and war against Russia, who is obviously threatened. This is not important to US interests, because Russia is not a threat to the US if they are left alone, and to make things worse, US funds NATO a lot. A neoconservative mindset briefly considered that staying in NATO was ok with the logic that it allowed us to "maintain influence in the regions" but with the repeated failure of police actions abroad, repeated failure of attempts to "influence" abroad, including 9/11 which was blowback for such "influence" attempts, the vietnam war which was an "influence" attempt against soviet communism, and on and, plus a flagging economy back home while billions and trillions are spent on this, has the conservative mindset falling back to the early-20th century isolationism. Influence is good but the cost is too high.
--The current power threat is not Russia, but China. By the original logic of NATO, if anything, there should be a NATO against China.
--Russia by itself is not a threat but could be potentially a useful bulwark against China or even against an uppity Europe. Russia joining forces with China would be bad or disastrous for the US. Therefore there is no benefit to the US in being aggressive toward Russia. NATO primarily exists, post-soviet union, for the purpose of being aggressive against Russia. Europe's security concerns aren't primarily a US problem and Europe should defend itself from Russia on its own dime, not ours. If anything, US should seek to maintain good relations with, and leverage over, Russia, because if we fail to do that, China will step in and use relations and leverage to woo Russia which does not benefit the US.
--NATO and expansion of NATO, even in the absence of the Soviet Threat which was the only reason US was really benefitting from NATO, has CAUSED Russia to perform the recent territorial invasions to try to secure their sphere of influence. This is not a theory; it's exactly what Russia said they would do, for exactly the reasons Russia said they would do them, all caused by NATO expansion and aggression exactly like Russia said not to do. And this aggression against Russia does not benefit the US at all, what's worse the US is funding and supporting it through the US's outsize contributions to NATO.
That's my attempt to fairly explain the American conservative standpoint that is "soft on Russia". Russia wasn't causing us any problem until NATO aggression caused Russia to start defending/expanding its territory, and even then, it doesn't cause the US a problem, it causes Europe a problem, except it does cause US a problem because of the NATO alliance and the fact that we are entangled in Europe. It has nothing to do with supposed theories about love for Putin.