The former--even Hitler and Stalin knew better than to use chemical weapons. Also, military experts, including those who had climbed a career ladder as chemical warfare experts, disdained them as militarily less effective and less desirable than explosives.Then why did they not use chemical weapons later in the war and not carpet bomb civilians specifically?
The latter...this is what we did do in Japan, pretty much. We used incendiaries instead of carpet bombing but the LeMay strategy was to burn up their cities pretty indiscriminately.
The question remains open. Did we have a double standard for the two foes, or was it purely a matter of military convenience based on there being better options for attempting precision in Europe?
Anyway even a strictly counterforce doctrine will in fact inflict a lot of terror in the form of civilian casualties.
When delivered via nuke, there is little practical distinction between counterforce and counterterror.