Most of them use those moves as utility and not for dishing out damage. Also, most Pokemon on your list have 1 or more moves of the opposite offensive category. Pelipper does use U-turn, but it also uses Scald, and some sets run Hurricane. Tornadus uses Focus blast/Heat Wave and Hurricane. Clefable has Knock Off, but it also uses Moonblast. Garchomp does run fire Blast, but it usually runs Scale Shot as well. Specially based garchomp is bad anyway. Magearna ran Iron head in Gen 7, when assault Vest sets were a thing. Now it usually runs Stored Power or Choice Specs, with no physical moves in sight. Moltres usually uses Scorching Sands and Flamethrower / Mystical Fire over U-turn. U-turn Zapdos is almost never used. Tapu Fini runs Scald/Surf and Moonblast/Draining Kiss too. Hydreigon almost never runs U-turn other than on Scarf sets which have less than 5% usage anyway, and those scarf sets use special moves like Draco Meteor, Earth power, Fire Blast, Dark Pulse. Special Blaziken sets are very rare
