Heh, the suggested (genocidal repression) policies have some predictable long term consequences.
1. Pissed off, violently anti-British post-guerrilla war regimes in the non-white colonies (NWC's). Not sure how instigating what amounts to blood vendetta with over a billion odd people and two major religions (Islam and Hinduism) is good for the British, but feel free to argue otherwise.
Not one colony would produce a movement that even required serious effort in stopping.
Fear and uselessness would keep them in line.
2. Foreign powers taking advantage both of the pissed off colonials (as pawns) and of WBE overstretch to wear down the WBE - there's too many fronts to try to defend against too many rising powers, especially given the technical and economic limits of the time.
Foreign powers would have their own Empires to worry about.
Only the USA and USSR wanted to destroy the European Empires.
3. Nothing suggested would butterfly away communism, nazism, fascism, or japanese militarism, and indeed could serve to encourage them. A WBE so heavily tied down in the NWC's is going to be in a horrid position once Hitler, Stalin, Tojo, and whomever else start making their moves.
The Nazis and Fascists would gladly go along with Britains Empire policy as both leaders stated.
Japan would not dare not to.
4. Britain gave up India and Ireland, among other things, because the average Brit wasn't a draka/nazi clone - gunning down defenseless civilians as a matter of policy is going too far for an large chunk of the homeland voters, an issue that will worsen, not lessen, as time goes on.
Strange how such strong policies on India and Ireland where so popular then.
5. Why in heaven's name would Australia, Canada, or Ireland want to drag themselves into such a predictable bloodbath, when the only outcome is a short term ego boost for some old farts in London, and long term troubles with the folks next door? Australia is not going to go out of its way to needlessly antagonize it's neighbors, and Canada is not going to endlessly support a policy stance that makes the old CSA look humanitarian by comparison. There is no way Ireland is going to support anything that strengthens the BE, given Irish history - they'll probably claim common cause (however wildly improbable/unjustified) with rebels elsewhere. New Zealand is vaguely plausible - but (like the other three) they lack the independent manpower pools or economic resources to offset the insurrection induced bleeding. Any serious attempt to do so would bleed the dominions white and probably incite earlier moves towards independence, not delay them.
Australians, Canadians etc viewed themselves as British in the past and as part of a Great Empire they would wish to keep it that way.
The Aussies and Kiwi's where read to fight with Britain at Suez.
N Zealand even in the Falklands.
Both countries has PM's who regarded themselves as British even in the 60's and 80's.
Non would be bled White and even if they did they would still be British and proud as they where after WW1.
6. There isn't enough power or influence in the world to prevent the nationalism 'virus' or the various anti-colonial, anti-imperial, and socialist memes from reaching the colonies. In all likelihood, accompanied by armed support. Result - widespread armed uprisings - not something the WBE's will have the manpower to handle, and not something that the voters at home will countenance for long in any event.
The voters at home will love a fight for Empire.
Where will these (millions mmm) of rebels get their guns?
7. WW2, Japan attacks WBE holdings in SE and begins push to India. In this ATL, the Japanese could easily be seen as a comparative savior by their 'fellow asians'. There's a real nightmare for you - Japanese attacks and native guerrilla insurgencies at the same time as the WBE is facing Hitler in Europe. No way that is going to end well for London.
The Japs could find themselves facing the full rath of the British Empire, Fascist Italy and Nazi Germany.
8. Heck, WW2 itself - why on earth would the US ally itself with a regime distinguishable from the nazis only by their accents? If the WBE managed by some warped miracle to hold together that long, the US would probably take advantage of WW2 to push the "blood thirsty madmen" out of NAm and conquer Canada, and the carribean colonies as well - not like the WBE will be in any position to dispute the matter. Don't hold your breath for any supply convoys or lend lease aid from the other side of the Atlantic either.