Context: During WW2 Alan Turing was essential to the efforts to break the Nazi Enigma code. In 1952 the British government chemically castrated him for being gay, in 1954 he took his life.
I don't know if Veritasium is a reliable source, but the recent video on Alan Turing made it seem like Alan had a good job and happy life for several years after WW2. Not defending that the UK government were pieces of shit, but I don't think it's accurate to say they turned on him "the second WW2 was over".
Edit: I checked another source. It was early 1952 that he was caught by the police in a homosexual relationship. So I guess he had around 6 happy years after the war.