But this also means that the British and by extension, the American’s knew too.
Of course the British and the Americans knew about the Holocaust. They knew about it and did everything within their power to put an end to it as soon as possible. There were lots of details they didn't know, but there was much they did know, and the truly remarkable efforts on the part of the Allies to save European Jewry should be better known and publicized.
Not necessarily the Americans, but it is pretty sure the Brits passed on their intel to the top.
Still, so what? The allies were already fighting to destroy the Nazis. It isn’t like they were sitting around doing entirely nothing!
They did. The Brits were decrypting ENIGMA reports being sent on almost a daily basis to RSHA headquarters in Berlin from the the Einsatzgruppen in Russia reporting body counts.