Are great Fast Bowlers slightly mentally unhinged?

A year ago I bought SA Sports Illustrated, it had an interview with the South African pace set-up. And all of them almost word for word, described the journey to superstardom the same way
"I always wanted to beat my opponent, not beat him up, but beat him"
"I wasnt looking at the medium-pacers or the slower bowlers growing up"

But the one that got a non-cricket playing mate of mine confused, was a portion where Allan Donald explains that he never wants to hurt an opponent, but if the guy gets hurt it happens, he will just get back to his mark and bowl the same ball, just faster!!

It reminded me of a story I read about a young Brett Lee, when he re-arranged the dental work of a fellow kid during u/12 cricket trials.
I mean, is this a characteristic found in other sports? If a tennis player had a thigh injury, most pros would be hesitant to cash in, but it fast bowlers seem like the type of people who would lure him to the net, and then try hit the thigh.

I remember when I was 14/15 I opened at a club match. One of the opposing bowlers was a man who has recently made a bit of a splash in international cricket. General nice guy. But in one spell, I think he didnt bowl one ball in my half of the pitch. I hit a few got laid out once, a few whizzed past my ear. But he didnt relent. To this day I think the man is unhinged!

I think unhinged is a bit unfair, but they certainly do need an aggressive side. They do need to keep their head whilst roughing up the batsman though. No point being overly aggressive for no reason. It always helps in unfavourable conditions if you can intimidate a batsman and get inside his head though.

A quote from Michael Holding from 'Fire in Babylon' (Great documentary, thoroughly recommend it). "I didn't go out there to hurt batsmen, sometimes they just got hurt".

Maybe a tad unfair, but I think it goes beyond agression though. They have this anger they can tap into that most people cant

I think there have been great fast bowlers in the history of the game have had that bit of mental instability/almost madness about their character, such as Merv Hughes, Fred Trueman, Jeff Thomson, Bob Willis. But then there are fast bowlers who are really nice guys both on the field and off it as well such as Terry Alderman, Ian Botham, Angus Fraser.

Bob Willis was practically in a trance when he bowled the Aussies out at Headingley in 1981. Bet he can't even remember how he did it. He was almost on auto-pilot.
I don't just think it's fast bowlers who have this mental streak. Sport, in general, brings out people's ruthlessness and you can be as nasty as you like - within the rules - and then be nice to your opponent(s) in the bar afterwards.

I think if they have that agression or mentality it improves them as bowlers.

Look at Morne Steyn, if he had that, he would have been one of the most dangerous short pitch bowlers in the world.

The greatest of all, Marshall, was just clever and quick of course. He did hit Andy Lloyd and Gatting but he never seemed to aggressive.