There are no double standards except in your gnat like mind.
The Quebec Referendum was moot, because there was nothing in the constitution that allowed it, although Canada did have plans ready to discuss Quebec's secession had they won by a significant margin.
The Scottish referendum was done with full consent of the British Parliament with the appropriate constitutional amendments.
Crimea was invaded by Russia and then had one of those Vlad-style votes, and we all know they're a pile of shit.
It was illegal under Ukrainian law and it is isn't internationally recognised by anyone but Vlad and his cronies.
In other words, it was a fucking dog and pony show.