US liberated Taiwan from Japan.
US owns Taiwan but is not a colonial power, but has never recognized PRC sovereignty over Taiwan. This goes back to 1949 and has never changed.
That’s why it seems so contradictory. On the one hand the U.S doesn’t recognise mainland China sovereignty over Taiwan but still sees Taiwan as a part of China. I understand why the U.S came up with this bizarre scensrio in 72 as a means of trying to maybe de communise China ( and of course make some money). I could be wrong, but Taiwan is probably the only territory that is seen as part of another but is considered a sovereign entity.