Crimea is in no way comparable to the Baltic States. It has a Russian speaking majority, while the referendum they staged there was likely falsified to an extent, most of the people living there did not really support the Ukrainian state and weren't particularly opposed to it Crimea being a part of Russia. In 2014 Ukraine was basically a failed state, economically and politically. At the time the average income in Russia was several times as large as in Ukraine (they are almost even now).
Geopolitically it made sense for the US and the West to largely ignore it. Due to their military presence there no one could argue that it wasn't Russia sphere of influence anyway. It was a small price to pay for ensuring that the the rest of Ukraine would shift it's alignment from Russia to EU/NATO (not having a Russian fleet stationed in one of your ports would likely make this move easier).
None of this in any way applies to the Baltic States.
Geopolitically it made sense for the US and the West to largely ignore it. Due to their military presence there no one could argue that it wasn't Russia sphere of influence anyway. It was a small price to pay for ensuring that the the rest of Ukraine would shift it's alignment from Russia to EU/NATO (not having a Russian fleet stationed in one of your ports would likely make this move easier).
None of this in any way applies to the Baltic States.