Because the term refers to a black who accepted a subservient role to whites.
It would depend on how it is used in a sentence. It is proper if you say "She was offended that he called her a name." or "He accidently offended that man." However, it cannot stand alone as a complete sentence.
That would be an uncle.
If he is your uncle by blood, his uncle is likely to be your great uncle. As to be an uncle it has to be a parents sibling. His parents would be your grandparents. So any of your grandparents siblings are typically called great uncles/aunts
she would be called your cousin. Maternal uncle's daughter is your cousin.
Depends on who is discussing him. He would be your first cousin.
You are no direct relation but as your wife would be an "Auntie" to him you would be called "Uncle".
It usually depends on context, but would you be offended if someone called you 'American' while on England?
If by "Uncle Tom" you mean a black American who always does what the white man says. Then i would say "slave". Uncle Tom is a very racist and outdated term, I'm not sure we need a synonym for it.
Probably, you would correct him. It depends on why he does it, and how you feel about it. If they have a child of their own, he/she is your half-brother or half-sister, so you wouldn't be their uncle.
The sister of your father or mother is called your aunt. Likewise, you would call the wife of an uncle your aunt.
If by "Uncle Tom" you mean a black American who always does what the white man says. Then i would say "slave". Uncle Tom is a very racist and outdated term, I'm not sure we need a synonym for it.
The tartan 'skirt' as worn by Scotsmen is called a 'Kilt' but don't let a Scotsman hear you refer to it as a 'skirt' as he would be VERY offended.