This human is for sure a complex being.
And more so is his environment.

It is a law, and if you wish you can call it a social law, that political and social matters cannot always remain the same. Change is inevitable.

Ummar Ibn Khattab [born 40 before Hijra / 584 CE in Mecca and died 23 Hijra / 644 CE in Medina], an administrator by excellence, ruled and rewarded people by merit.
In other words, he had a class system but it was based on merit not on lineage, not on colour of skin and not on wealth.

So during his leadership Bilal (the ex-slave), Suhaib (the ‘Roman’) and Salman (the Persian) were given preferential treatment compared to Abu Sufyan and other influential figures from the Quraysh tribe.
There is for example a record where he received Bilal while he kept Abu Sufyan waiting to be received.
Abu Sufyan used to be the leader of the people of Mecca while Bilal used to be their slave.
There are further records about distribution of wealth during his time.
Umar was tough on himself, his family and especially the tribe of Quraysh.
You could say that the majority of the tribe of Quraysh found it hard to breath under his leadership.
Ummar’s type is indeed rare in human history and it is not strange that he was hated by many people.
He was assassinated.
Many researchers have accused the influential tribe of Quraysh.

One of Umar’s mottoes is: “Do not put off today’s work for tomorrow.”

Today, many claim to like him but their practice says otherwise.
If he was among us, the Sunnis would throw him under the bus before the Shias.
You cannot be fair and expect everyone to like you.

There has to be change. It is a law.