Russia caused this. If we shut down Russian infrastructure and Russian civilians get caught in the crossfire, the Russian government can blame themselves. You cannot expect to engage in acts of war without endangering your own citizens to at least some degree. To engage in war is to invite it to your homeland.
Hell, if we don’t retaliate, we may be seen as a weak and an easy target. I argue that we already are, in the realm of cybersecurity, which is why state-sponsored attacks on American companies keep happening.
Furthermore, American infrastructure, companies, and civilians come first. It should be made clear that we will deal with aggressors and acts of war. Countries do not attack the US in the physical realm out of fear of retaliation, and it should stay that way in the cyber realm.