"in its modern form, has not always existed"
Stopped reading here... morphed it, changed it, strengthened it, etc. =/= created it.
@ the very idea
The author wrote, "
certainly in its modern form," probably to preempt critics who would talk about examples of xenophobia and tribalism in earlier human societies.
But did you read the articles I linked?

Madvillain said that some pages were missing from what he posted, so it probably isn't as clear as it could be. The articles I linked provide more evidence and deepen the argument.
On a side note,
of course capitalism did not create every social phenomenon in the world today. After all, it is a fairly recent development. But it has shaped/conditioned every social phenomenon and directed them to its ends. So capitalism didn't create xenophobia, etc. But these concepts were handed down and, under the capitalist mode of production, shaped to create new concepts (e.g., racism) that fit the conditions of the era.