What does the feudal past of Tibet have to do with anything? Are the "Free Tibet" people covertly arguing for a return to feudalism?

It's like a weird Chinese version of the White Man's Burden. They were "uncivilized" once upon a time, so now they deserve occupation.

Just like native Americans, except there is no sufficiently strong military power to bake and support "liberating" movement within US, so they just sit tight in reservations and nobody wants to "rescue" them.

Liberate and rescue them from what? They live on their own land and decide, to some degree, their own law. At the same time, they have the rights of full citizens.

The article you linked to is poor mostly because it's liberally bathed in whataboutism. Tibet's backwardness has nothing to do nor does it justify China's actions in Tibet. Two wrongs don't make a right.

Let's do a quick bias check: do you believe most Tibetans would secede given the vote?

I don't think they would, but neither do I know the statistic. If anyone can provide it (I couldn't), then if they would indeed vote to secede, I'll change my mind.

by this metric Taiwan must be third world country, they had same starting position after WW2 as China and look how they made it without glorious CCP...

same goes for Tibet, you think without China they would stay in same place? it's like those people from post communists countries feeling nostalgia about communists and what everything they built forgetting what was built in non Communist countries, you know life goes on with it without Communist party, without usually goes better