A. People referencing strength also mentioned Hancock easily stopping a speeding train, with several carriages, dead in its tracks.
B. Mjolnir amplifies the power of Thor's strikes. Odin literally said, "its power has no equal". If Thor could level multiple city blocks through pure strength, just by hitting the ground, he wouldn't have to bother using his hammer all the time. Not to mention he would be physically stronger than the Hulk, which he isn't.