So it seems that Morrowind was invaded by Argonians. I also remember a dark elf on the island, talking about some slaughter caused by the Argonians (perhaps if racism was added, she could say "your horrible people" if she is talking to a Argonian dragonborn).

So i think it would make some sense, that if you are a argonian dragonborn visting the island, you should encounter more racism, then a non-Argonian dragonborn would.

It would just be more realistic.

What do you think?

Could add a little bit of flavour, although I think they recognize you as an Argonian not from Blackmarsh. On a side note, the Dunmer got what was coming to them.