Because the archipelago standing of the north-west coast of Europe is entirely dominated by the island of Great Britain, the largest and most populous island in the archipelago. This is a normal...
the isle of thanet was called the isle of tanet because the man that came up with the name was called Frank Isle Thanet
Pine trees thrive there.
I have no idea how it got its name, but it is the Isle of "Wight", not white.
The Isle of Bute is sometimes just known as Bute and in Scottish Gaelic it is Eilean Bhòid.