"And the Irish depending on potato"

You'd be surprised. Medieval and early Renaissance Europe were far from culturally sensitive*, but they regarded people in Asia and Africa as fundamentally similar to themselves. Racism evolved out of the discovery of the New World - at first, as a means of justifying the murder and enslavement of American peoples, and then, after the Pope said that colonizers had to pretend to care about Christianized native lives, as an excuse to seek exploitable labor elsewhere (Africa). Even in the 17th century the divides were far from firm - only going into the 18th did social divisions harden, and not until the end of the 18th century did 'scientific' racism truly emerge.

*my personal favorite is in a 12th or 13th century chivalric romance, a character is mixed-race - the European author apparently had no idea what someone who's mixed race would look like, and so described them as literally half-white and half-black, split down the middle

Racism has been present for a lot of human history. The modern western version of Christian white supremacy can be traced back to the Greeks, then on to the Arabs who, inspired by the Greeks, used their conception of race to justify their already present slave trade. For the Arabs it's wasn't so much "we're superior so we have a right to enslave these people" as it was "we were able to enslave these people because we are superior". European Christians, armed with "the curse of ham" took those Greek ideals and pushed racial heirarchy and supremacy to the cultural forefront around the 15th century and it's shaped their societies, colonies or otherwise ever since. It's obviously evolved and changed over time but that's the gist of it. Racism isn't new, but European christian empires made it into the monster it is today

the rest of the world: "Amsterdam is such a biking paradise!"

dutch people: "jesus cancersucking christwhore amsterdam is a wretched hive of scum and villainy filled with cars, can't even bike safely on the highway!"