It was a joke... but also at least a million of them were killed, they're now an ethnic minority in Tibet, practice of their spiritual beliefs is either outright banned or strictly controlled.

Being Tibetan means something very different than it meant prior to 1959.

> they're now an ethnic minority in Tibet, practice of their spiritual beliefs is either outright banned or strictly controlled.

Not according to Wikipedia:

"In 2011 the Tibetan population was three million.[33] The ethnic Tibetans, comprising 90.48% of the population,[34] mainly adhere to Tibetan Buddhism and Bön, although there is an ethnic Tibetan Muslim community."

Also not according to my personal experience. I've never been to the Tibetan Autonomous Region, but I have been to an ethnically Tibetan part of Sichuan, and you certainly see a majority of people who look Tibetan, people speak the Tibetan language, taxi drivers ask if you don't mind if they stop and pray at Tibetan Buddhist shrines along the road, restaurants serve yak butter tea, and so on. There's simply no way to claim that Tibetan culture is gone or even endangered.

90% of the population of Tibet is of tibetan ethnicity and there are areas of tibetan majority outside of the autonomous region (sometimes referred to as greater Tibet)

People practice their religion openly.