EDIT: This question was unclear before, I have tried to clarify it.
This is on the first page of Google results for the query "George Bernard Shaw": George Bernard Shaw Defends Hitler, Mass Murder.
I have a hard time taking the video seriously, but I do not know enough to actually refute it. The video makes incredible claims, like "The Left" supporting Hitler because he would kill people. Also that Marxian Socialism was about killing of "the parasites of society". And that eugenics was about killing off people based on class.
The Wikipedia article on him lists several sources (none of which I can see or confirm) that the speech they use as evidence was just a joke on the more extreme eugenics camps (reductio ad absurdum).
Here's related stuff that I've found that don't directly have to do with the claims made by the video:
This quote from a play that he wrote which is decidedly unsympathetic to Hitler, Buoyant Billions (1946-48):
Why appeal to the mob when ninety five per cent of them do not understand politics, and can do nothing but mischief without leaders? And what sort of leaders do they vote for? For Titus Oates and Lord George Gordon with their Popish plots, for Hitlers who call on them to exterminate Jews, for Mussolinis who rally them to nationalist dreams of glory and empire in which all foreigners are enemies to be subjugated.
And a defense of the Irish Prime Minister expressing condolences to the German ambassador upon Hitler's death. This, too, seems vague, since he says it was the chivalrous thing to do, and accordance to diplomatic protocol. This could be taken as a "Screw you" to England or a call to humanity to even the most inhumane. Or as the page implies, that he was sympathetic to Hitler.