Running a big forum isn't easy. SM is big, SF is ludicrous. It's hard to manage things when they get that big, they tend to develop a life of their own.
However I will say that management skills are management skills.
When it comes to forums, the folks in charge are rarely there because they were selected for skill set. In the case of SF, a lot of the staff were put where they are for a bunch of different reasons. Who they work for, who they are friends for, popularity, etc... I doubt many of them were chosen based on the criteria of having the requisite skills for the job.
If folks don't have a management skill set, they tend to fall back on just being more and more harsh over time until they become assholes. I know I'm known for being very harsh, but I'm generally fair as well. (As for being an asshole, I was like that long before this place was around...

)
I do agree, Brad is vicious. The users at SF have made him that way. The same thing was starting to happen to our staff here last year. The difference is we recognized it and did something to stop it before it got out of hand.
That's why we downed the site for a day, banned the very small handful of people that were causing us to make the rules more harsh and moved on.
(I will point out that since we banned those folks, we haven't had to add any new conduct rules, in fact we've backed off on enforcement of some of the older ones....)
In a lot of cases, I'll bet the power that some mods wield at SF is the most power they have ever had anywhere. The temptation has to be to become a petty tyrant and to get high on it. For many folks, it's very easy to fall into the trap of becoming a tyrant. It happens out here in the real world all the time when people who aren't suited for a job wind up in charge. You've all seen it. The manager who seems to go out of the way to fuck with his staff, changing people's work hours all the time for seemingly no purpose, etc, etc...
When you're used to managing multi-million dollar budgets and hundreds of people it's a lot easier to not be influenced that way.
Regardless, SF has a right to be run the way the people who own it want to run it. Petitions are generally a waste of time in cases like this.
P.S. - I have never been banned from SF either Tanya. ;p