A player can be aggressive but controlled at the same time. A player who keeps getting sent off in high octane games lacks self-discipline and lets his team mates down.
He's been sent off eight times in his career, twice against Everton, twice against Man United, once against Chelsea & once against Leeds, which rather suggests he does have issues controlling his temper when in a pressure situation...
Anyhoo, I'd feel pretty much the same about him as I did...