https://twitter.com/DiginomicsNews/status/705258811192438784
https://twitter.com/DiginomicsNews/status/705258811192438784
If you want to promote Ethereum, you can do so on /r/ethereum/.
I am sure promoting dog ownership over cats is frowned upon by /r/cats readers, too.
You are wrong, nobody on /r/cats have gotten their comment removed or been banned for talking about dogs or any other pet on /r/cats.
Similarly, I've never seen anyone upset about people discussing non-Javascript languages in /r/javascript; there's specific subreddits for some popular variants and libraries (like /r/coffeescript and /r/react), but nobody cares. The rules do say posts should be at least indirectly related to javascript, but a post talking about a better language would be seen as easily related enough.
/r/bitcoins rules do not follow the norms for Reddit communities, as far as I've seen.