We're also all genetically derived from ameobas. Not the greatest argument.
Oh and after watching that video, the kid was right in what he said and the other guy was yet another boring "you're secretly raaaaaaaacist" type that basically everybody on the planet has had enough of their intellectual dishonesty.
He said that immigration over the past 2000 from various regimes has created the cultural and genetic makeup of this country. That is factually, inarguably 100% objectively a true statement. To believe otherwise is to believe that either different populations didn't have different genetics, and I'll point you to any high school biology class if you believe this, or that the peoples who invaded or immigrated had zero sex or assimilation in the country to which I'd point you to any possible musuem or history book. What is it you people think places like 23 and Me do (spart from scam, obviously)? What do you think epigenetics are?
The idea that the UK was a mishmash of cultural and genetic populations over the 2000 years is not just a factual statement but used to be somewhat a source of fun. But this guy heard the word "genetic" so immediately decided to put words in the kids mouth and of course because social media has zero critical thinking skills or rationality about "the other team" and are desperate to constantly hit these irrelevant and tedious Gotchas then of course we've now got people being implied to be a racist for using the word "genetic"