For me, the Holocaust is a real emotional thing.  I had no grandparents growing up, but we spent lots of time in our apartments in Miami in a Jewish enclave, I guess.  It was a gated community on North Miami Beach with three towers, a little convenience store, a restaurant and pool, and Dock slips for boats.  And so my babysitters were retired Jewish retirees, most of whom were holocaust survivors.  I was 2 or 3, the first time I heard of the Holocaust.  I was spending the night with the Fusses, whom I called Grandma and Grandpa Fuss.  I had taken a number and written numbers on my arm, to be like them.  I didn’t understand why it horrified these two Holocaust survivors.  I still remember the tears pouring down Grandma Fusses face as she scrubbed my arm with a sponge from the kitchen.  Eventually, I learned their story.  Two people who were the only survivors of their families who found love after the camps.  I heard about their parents and siblings who died in the camps.  I remember that one of their sisters was a ballerina.  She was a teenager when she went into the camps and she ade it through the initial separation because  a guard thought she was beautiful. As an adult, I know what that meant but as a child I remember thinking it was so beautiful  that she gave the food to her sister. He would take her to his office and have her dance for him.  She would come back with extra food for grandma Fuss and cry herself to sleep.  She never made it out of the camps.  And though it hurt, Grandma Fuss to tell me that story, she did it in whispers and with tears.  She told me it was my job to remember her sister, the ballerina, always and forever a teenager.  
I was in 1st grade before I thought of it again, in a meaningful way.  I went to school in our temples basement in Dunwoody, Georgia.  and one Monday we didn’t have school.  Over the weekend someone had broken in and defaced desks, couches and chalkboards with swastikas.  I saw that symbol and remembered Grandma Fusses tears.  And I knew that it was evil and I was hated.  I never understood what those teenagers were thinking as they painted a symbol of hate or scratched it into surfaces.
I am shocked and horrified at the news today that Hitler never gassed his own people.  I know that is not true.  I am one generation removed from the survivors.  Their children were my parents generation.  As we remember our flight from Egypt this week, so too do Jews remember the Holocaust.  Last year, Elie Wiesel , a Holocaust survivor, and Nobel Laureate author, died.  He has many quotes…too many to list about why Jews wrote down their memories for my generation and forward.  Read his Nobel speech, or even just the quotes that come up on google.  We remember the generation lost.  All 6,000,000 of them.  Men and women, Mothers and Fathers, Children and Artists, Brothers and Sisters.  
But I want to be real here.  These are the approximate numbers:
Number of Deaths
Jews: up to 6 million
Soviet civilians: around 7 million (including 1.3 Soviet Jewish civilians, who are included in the 6 million figure for Jews)
Soviet prisoners of war: around 3 million (including about 50,000 Jewish soldiers)
Non-Jewish Polish civilians: around 1.8 million (including between 50,000 and 100,000 members of the Polish elites)
Serb civilians (on the territory of Croatia, Bosnia and Herzegovina): 312,000
People with disabilities living in institutions: up to 250,000
Roma (Gypsies): 196,000–220,000
Jehovah’s Witnesses: Around 1,900
Repeat criminal offenders and so-called asocials: at least 70,000
German political opponents and resistance activists in Axis-occupied territory: undetermined
Homosexuals: hundreds, possibly thousands (possibly also counted in part under the 70,000 repeat criminal offenders and so-called asocials noted above)
But, Hitler never used chemical weapons on his own people
https://www.quora.com/Why-should-we-never-forget-the-Holocaust