riddle - Does he like them or not? Another Grandpa Mystery

Now I know very well the weird likes and dislikes of Grandpa.

Yesterday he tells me:

"Son

I like Queen but not the Queen

I liked the King but not the King

I like Monarch but not Monarchs

I like Prince but not the Prince"

Wha does he like and dislike? Why?

Answer

He likes

Musical Royalty, but not Actual Royalty

I like Queen but not the Queen

The band Queen, but not a royal Queen

I liked the King but not the King

Elvis Presley, but not a royal King

I like Monarch but not Monarchs

The band Monarch, but not royal Monarchs

I like Prince but not the Prince

The singer Prince, but not a royal Prince