[watchfirst9]

after ww2 ended japan rtn taiwan to china which at that time was still ruled by kmt

ccp only came in in 1949

I can see you never read Jap emperor surrender statement and documents
It is return to China by Laws. 
https://www.youtube.com/watch?v=4ju-KSn9Ozo

The fact Jap write its surrender and return to is to China, never said it must be ROC.
So whoever is the govt of Chn, own Tw islands. 
Tw is never out of UN, as internationally always put remain part of Chn.

Anyway those Twese deny their roots is rather disgusting, their actions similar culture revolution in mid 60s- mid 70s.