A troll or flamer is (adapted from this):
1. A name-caller
8. Blind to his own faults
10. Unable to take responsibility for his words
Proverbs 26: 4-5
Do not answer a fool according to his folly,
Or you will also be like him.
Answer a fool as his folly deserves,
That he not be wise in his own eyes.
The wise of heart will receive commands,
But a babbling fool will be ruined.
A fool does not delight in understanding,
But only in revealing his own mind.