The British were building those factories or having them built between 1938 and 1941. They didn't have a shortage of workers, they couldn't have otherwise they wouldn't have sent millions of men and women to death camps, would they?
I suggest you simply recuse yourself from talking about this as you know more falsehoods than correct info about it. You seem to hijack a thread with this stuff when an argument isn't going the way you want it?
Reductio ad Hitlerum
If you want to inform yourself perhaps read:
Arming the Luftwaffe by Daniel Uziel.
as it covers the use of impressed and forced labour.
1 I can talk about the millions of Indians and Bangladeshis Churchill and Cherwell Lindeman Britain starved to death during WW2 because they as imperialists controlled the foreign exchange and food supply of Indian and put English people first. When put to the test Britain, Cherwell, Churchill did exactly the same thing as the Nazis or the Communist Russians did to the Ukrainians. Food for their own people first. It certainly helped Britain win the war.
2 We can go back to the Genocide of the Irish when over 50% of the British Army was stationed in Ireland, the regiments locations have been tracked and recorded. They made sure that the Wheat, Barley, Rye, Oats, Butter, Sheep, Beef was taken from Irish and taken to Britain and that they starved rather than some London Banker miss out. If the Constabulary didn't manage to take away the food, the Militia came in and if they failed the British Army Came in and they never failed. I note the Prussian empire never starved its Polish Lithuanian subjects when they had a Potato Blight. All so that banks could get paid and Britain could industrialise.
3 We can also perhaps mention the that in order to expand their diamond, gold and mineral interests the British decided to take control of South Africa, displace the Governments the Afrikaaner people had chosen and dealt with local resistance by putting Women, children, grandparents in concentration camps feeding them of poor food lacking in vitamins and freshness. Fish an rice. Photographs of typhus victims there looks like something out of Bergen Belsen only there was no excuse of knocked out water, electricity, sewage and food distribution.
The anger felt by Dutch and Germans to these crimes in South Africa is one of the factors that caused bad feelings and cynicism and helped trigger World War 1
All of these crimes made Britain powerful and wealthy.
Shall I bring these things up every time we discuss something? Certainly I can the Bangladeshi/Indian famine? I'm not going to though.
I should point out there were 4000 people in concentration camps prior to WW2 and most of them were there for short sentences for essentially political speech crimes. Forced labour was not a big component of the early war years.
Companies like Junkers used no slave labour.
Heinkel had the fortune or misfortune of being near a Russian POW camp who were hired out the prisoners to Heinkel. The poor souls were underfed couldn't perform and the soviets would have executed them if they got back to the USSR.
Certainly you can talk about these things and should be but there is a way of doing it not with generalisations, sweeping statements and rhetoric.
I think it was in Arming the Luftwaffe by Daniel Uziel that he noted that big factories often had a concentration cam attached in which the German workers themselves were sentenced. He notes and secretary at Daimler Benz who suffered this for 2 weeks for her attitude.