i'm not sure how you would expect anyone in westeros to have even a slightly positive view of the unsullied or the dothraki.
also, cersei is brainwashing people on her side by telling the truth about dany. what a world.
I don't think they would have a positive view of anyone foreign.
It's just that Cersei is not loved by anyone. She rules by exactly the same principles with which she wishes to distinguish herself from Dany.
-Dubious claim to the throne (read: she has none, no one believes her sons were legitimate)
-Burns her enemies alive. As Olenna pointed out, Margaery was loved by all and she killed her.
-Seeking the help of the truly vile. Just a week before, she negotiated (although without bearing fruit at that point) with Euron Greyjoy, a notorious pirate whose greatest claim to fame is rebelling against the crown. Breaking guest right at the red wedding with the help of Walder Frey.
Cersei has absolutely no grounds on which to play this card. She has disregarded the traditions of her homeland at every turn by ripping up royal decrees, killing rightful queens, committing adultery, and other crimes that she will never have to answer for.
Ned Stark, who was the most lawful and loyal servant anyone ever saw defied Robert Baratheon when he suggested killing Dany and her foreign savages.
Now Cersei has the gall to put forth the notion that she fights for her homeland, even though she has stood idly by as her own soldiers raped and pillaged the otherwise peaceful countryside.
Cersei has no faith, no country, and no honor to claim Westeros as her own, so she has no right to say it isn't Dany's.