True enough, but in terms of the Cullen-as-villain scenario I would point out that the writer who did it before was the character's creator so I think that carries a bit of weight in terms of whether or not such a direction would be inappropriate or out of character.
I agree, and I do wonder if Tini is intending that Cullen is being influenced by the demon inside. If so, it hasn't been made explicit yet but it would explain a few things in terms of his unexpected behaviour.
I'm not happy with this particular direction for him myself (as I acknowledged in my original post). I agree that some of these traits are entirely unexpected. Some of the aristocrat stuff can maybe be explained as just him embracing some of his family money, heritage, etc as he's gotten older off-panel...but it certainly is a shocking jump from where we last saw him. I do think it would help to have some in-story acknowledgement of and explanation for the change in who Cullen is now from who he was last we saw him.
In terms of his current anti-mutant attitude, I'm not sure it can entirely be classified as racism. I think its more about the massive shift in the political situation of Krakoa than it is about mutants as a people/race. Practically overnight they went from having no political power within the MU to having their own nation; with massive political influence with their valued exports, etc; with mysterious teleporting gateways that only they can use, given them access to every other country on Earth; every single one of their citizens has super-powers; and some of the leaders of that country are known terrorists, psychopaths, mass murderers, etc, because being a mutant automatically gave them all a clean slate and diplomatic immunity for their literal crimes against humanity.
That is an absolutely terrifying situation for the rest of the world from a national security perspective. Even the non-mutant haters and people who love and trust the X-Men are still upset and suspicious due to the presence of people like Magneto, Apocalypse, Exodus, etc, in the leadership.
I'm absolutely not saying Cullen is right in his actions here...I'm just saying that having developed fears and concerns about mutant society at the moment is not necessarily a matter of racism, but rather a matter of fear over a massive and sudden shift in the balance of power.