- I had from the beginning espoused a non-religious view of Buddhism. About 20 years in, my teacher stated that Buddhism was definitely religious, and that devotional practices like pujas were non-optional. I didn't like it, but if you take on a teacher, it behoves you to at least try to go along with the teaching - which I did.
- I learned some things about Tibetan history that were the opposite of my earlier, naive beliefs. Pre-communist Tibet was not Shangri-La.
- While I never practiced tantra, the tradition was tantric; I eventually learned some important things about tantra that I found unacceptably obnoxious. I can't go into detail, because I don't want to undermine anyone else's commitment to tantra.
- The group that I had been involved with gradually changed, I became an outsider, and things got difficult. Friends in the group cut me off.
- The behaviour of Buddhist nationalists in places like Myanmar and Srilanka towards non-Buddhist minorities appalled me - this was the tipping point.
- I did my back in through long sitting sessions. The amount of my life that I had spent sitting was beginning to look like heavy expenditure for no obvious gain (I wasn't making much progress).
These are my reasons; they don't apply to anyone else, and I don't deprecate Buddhism or Buddhists. I just gradually came to see that I'm no longer one of them.
There is a great deal that I integrated from Buddhism. It remains the basis for my morality, and my world-view is still largely based on Buddhist thought. But I no longer do any kind of formal practice, and I don't identify as a Buddhist.
I avoid articles about pay in the SF area, AI models, Tesla cars, and many other topics. If I read one by accident, I just move on - I don't post a comment whingeing that I'm not interested.
I don't belong to an "in-group" here; I used to be a Buddhist, but I no longer profess any religion. The subject still interests me though; I devoted 40 years of my life to it, and unsurprisingly it has had quite an impact on me.
For what it's worth, a tulku in Tibetan Buddhism is a re-incarnating lama. I realise that I used the wrong word; what I meant was "terton", which is a revealer of hidden teachings. Those hidden/revealed teachings are a specialty of a minority of Tibetan Buddhists - so an "in group", almost by definition. Tertons an interesting subject - if you happen to be interested in such things.