It's a bit soon to be saying she's being treated differently. The specific scenario of someone going off to join a terrorist organisation which unilaterally declares itself to be the government of a a new country is something we haven't really seen before. I think everyone, our government included, is making up the rules as it goes along.
From a legal perspective, I'm sure this dreadful woman has the right to return to the UK. I'm equally sure she'll be a burden on this country for the rest of her life. This perception has absolutely nothing to do with the colour of her skin (or her eyes, or her hair, or her shoes...) - but it has everything to do with her actions.
Let's be entirely honest, if this problem somehow 'went away' , not many people would lose any sleep over it.