reg wrote:why are these demons or demonic forces or whatever so bent on harming or interfering with others' spiritual practice?
They are dedicated to evil and want to turn at least our world into a hell realm. I realize this sounds like an episode from Buffy, but it's basically the case. HH Penor Rinpoche mentioned this at least once with respect to demons encouraging tobacco smoking (of course Nyingma masters can be a bit over the top wrt this issue). I have also heard some other masters refer to demonic activity. Generally though TB teachers don't talk about it that much.
To me that kind of idea is sort of reminiscent of a cartoon villain twisting his moustache while cackling, or the behavior of a jealous child who takes it upon himself to sabotage things.
That is exactly the case. The beings have become insane or totally intoxicated with the negativities.
If such is the case, then why/how would a being with such confused/petty/unwholesome motivations have the power to seriously threaten someone who is presumably being protected by the blessing power of the Buddhas and bodhisattvas?
Well they don't have this power directly. However some of them have acquired power from mantra practice in previous lifetimes and have then become like rudras. So please take a look at the legend of the origin of Vajrakilaya and this is the basic story of demons acquiring power (and in this case taking over the world). There are other such legends too.
But their main power comes from promoting negativities amongst non-Dharmic people or attacking just Joe/Jane practitioner with their vulnerabilities. So something like a genocidal situation is probably a result of the minds of beings being inflamed by demons (although with humans around, who really needs demons - the answer is that humans don't have a long term goal to turn the Earth into a hell realm and some of these demonic beings do - so they are like extreme sociopaths).
Please note the paragraph above is my opinion - I have not heard a teacher actually say this. As I said they don't tend to talk about negative forces that much. Most of the harm comes from fellow humans and their negativities.
Another source of this is from the Chokgyur Lingpa lineage. In "Blazing Splendor" Tulku Urgyen talks about his grandfather dealing with demons a bit. There is also the tale of an eccentric teacher of Tulku Urgyen who lives under a tree who goes out and throws a torma once a day to keep the demons from China from invading (he also says that this can't be stopped but there is great merit in throwing the torma).
So the karma involved is complex and far above my paygrade as we used to say in the military.