Don't underestimate people who have unpleasant beliefs... easy to treat them as a joke but actually a lot of the Nazis held doctorates.. if they weren't so clever & manipulative then they would never have got into power.
If the Nazis were 'just a joke' then their beliefs would not have spread around the world & people would not still hold similar beliefs today. People are actually getting regularly murdered in countries such as the Ukraine where neo-Nazi parties have a large amount of support
The Nazis did not wish to 'eliminate' Jehovah's Witnesses - they wanted to re-educate them. JWs were sent to concentration camps if they refused to stop preaching the Bible & renounce their belief in God's word over Hitler's. The men were shot as traitors if they refused to join the Army.
Any German homosexual who continued to live an openly gay lifestyle was imprisoned. The aim of the Nazis was to encourage people to marry & have lots of 'perfect German children' - so homosexuals who refused to deny their sexuality were sent to concentration camps.
Sadly those convicted of homosexual acts were often not set free at the end of the war - as it remained illegal to commit those acts for years in Germany just as in the UK.
In Germany the small minority of black people & mixed race people (with one black parent) were shunned, often sterilised & sometimes experimented on. They were badly persecuted but rarely routinely killed.
Not all disabled or sick people were subjected to the euthanasia action.
Instead the Nazis concentrated on getting rid of the seriously mentally ill & learning disabled elements of the population (eg schizophrenics, Down's Syndrome children); also those who were said to be suffering from certain 'hereditary abnormalities' (which weren't actually hereditary!) such as epilepsy. Again; the Nazis weren't stupid as they didn't wish to alienate many Germans - they mainly got rid of the groups who were already stigmatised & rejected before they came to power.
The main two groups that the Nazis attempted to eliminate (with the assistance of many in the occupied lands) were the Jews & Roma.
Germans with 1 Roma grandparent were at risk of being exterminated just as much as 'full' Roma people all over Europe - because the Nazis saw 'mixed Roma blood' as an 'anti-social threat to German blood'.
The Nazis saw the Jews as a racial group, not a religious group, & still killed those whose ancestors had converted to Christianity.
Those who had only 1 Jewish grandparent were left alone IF they did not 'look Jewish'. The Nazis continued to murder Jews & Roma until the last days of the war.
The Nazi policies towards the Slavic peoples of Eastern & South-Eastern Europe were confusing. Slavs were seen as 'sub-humans' to be used as slave labour when it suited Hitler; but some were allowed to be 'Aryanised' & become Nazi soldiers.
Some Slavs hated the Jews, Roma & Soviet Union (Communists) so much that they were willing to join the Nazis. Nazism also appealed to the strong Nationalist sentiment in the Ukraine & other countries; they knew the Nazis despised them but they hated & resented the Communists & Jews more.
The historic hatreds of the Jews, Roma & Communists are the reason for the large amount of support in Poland & the Ukraine for the neo-Nazi groups that formed after the Cold war finished.
It's ironic because the Nazis massacred or indirectly caused the deaths of millions of non-Jewish & non-Roma Slavic people too - especially Poles, Russians, Serbs & Belarussians.