Struggling with the focus on rebirth in Tibetan Buddhism
After close to 20 years practicing Zen, I have lately become very attracted to Tibetan Buddhism, specifically lojong and the focus on cultivating bodhicitta. However I'm really struggling with the focus on rebirth, and specifically, the idea that we get better or worse rebirths depending on our behaviour in previous lives. I find a lot of the arguments for this unconvincing or worse actively harmful.
For example, I was listening to one teacher saying that if we believe this life is all there is that our practice is in vain. This view seems to confuse "is" and "ought", and also attaches to some idea of a self that 'develops' or 'progresses'.
I also worry (and I realise that this point comes dangerously close to breaking one of the forum rules, so please notes I am a sibling in the Dharma) that this view was used to maintain class power, in that if one was born a peasant, the notion of rebirth justifies that position in life.
There is no real evidence beyond the anecdotal as far as I can tell that we transmigrate from one life to the next. The Buddha refused to answer the question of what happens after we die, and rebirth is not one of the four seals of the Dharma.
I have my own understanding of rebirth that we are all ultimately the same substance in the universe, but our attachment to this form causes delusion. Is my lack of belief in some parts of what Tibetan Buddhist teachers say a deal-breaker? I want to continue this practice more as I feel it is a powerful way to help all sentient beings escape suffering