I'm unclear whether you're arguing that obscene/pornographic material should be accessible/distributed to minors as the distinction here is that this activity is in fact a federal crime in the US (and most of the world).

The government unequivocally has the right and obligation to enforce federal law. To what extent and by which mechanisms they should do this is a different question altogether but this issue is hardly about 'dictating what other people can do with their own lives in their homes' as was the case with other laws like anti-LGBT.