What does astound me is the level of openness about their hatred for the UK given that they want to be an independent country and presumably be taken seriously as such. If Scotland were to become independent all these petty side swipes at other nations would fall well short of the level of diplomacy required to get on on the world stage.
But would they still make the petty side swipes at other nations if they weren't included in the thing they're swiping about?
A lot of people dislike the establishment of the UK. They dislike "the UK". That's not the same as swiping at the people of England or Northern Ireland or Wales.
And "speaking for Scotland" is a very established form of humour on Twitter etc. There are whole corners of the internet devoted to people who "speak for Scotland" on Twitter.
I'm not a diehard SNP fan, didn't vote for them, really dislike many of their policies and am undecided how I'd vote if indy2 happened, and I think this was ill-judged and not something I would ever tweet (especially if I was in the public eye etc)... but I think this is making a mountain out of a molehill to be honest. There is enough anti-English sentiment around without trying to find it in "lighthearted" tweets about the UK and the Eurovision. And as I said above, it's unhelpful to conflate the UK with England because that's exactly what people who want independence have a problem with (amongst other things).
(Inverted commas around lighthearted because I think that was the woman's intent behind the tweet).