I’m not sure the US should allocate resources to do that either. But that’s irrelevant, all countries have an interest in the success of their industry, and the strength of their utility infrastructure. These things have been a matter of political interest for millennia.
Besides the simple economic downsides of not selling the product, there are concerns about implementing critical infrastructure with a more nebulous chain-of-custody or engineering governance model.
Companies that manufacture critical infrastructure within one's own legal/political jurisdiction(s) can be held accountable -- whereas those actions wouldn't be as possible for those outside of that jurisdiction.
Or to put it more bluntly -- cyber warfare has been going strong for at least a couple of decades now and has only escalated in recent years.
