There are freeways (Interstate 5 anyone?) where 100mph is child's play. Sections of road so straight and empty and isolated (yet still major thouroughfares) that a 70mph limit doesnt make much sense. In places like that, I really dont see the harm in going 100mph, especially on a modern machine clearly capable of travelling at that speed without losing much stability.
Now. That said..... I learned my lesson with travelling that fast. About 5 years ago I got pulled over doing 120 in a 65 zone in my (first) car. It was 1:00AM, there was no traffic on the road, and I was just cruising. I got nabbed, pulled over, tested, searched, chastized, etc, etc, etc....but I got a warning. Ever since then, Ive slowed down quite a bit. I still speed, but not to that extent. My rule is this: I move through traffic, just a little bit faster than the rest of the guys on the road. If traffic is doing 75, I'll do 80ish, and so on. Traffic around here in the bay area tends to move quickly (when it isnt jammed), so I spend most of my freeway time ay 80+ mph. I've been following that rule for 5 years in both cars and on bikes since I started riding, and havent been pulled over once, even though I've gone past (and been passed by) many cops, CHP, sherrifs, etc.
So, if this guy was doing 125 weaving through traffic (though I'd like to have seen what constitited 'traffic' in this circumstance), prosecute him. BUT prosecute him for the weaving, the massive speed differential, and the disrespect to other drivers. not the outright speed.
Traffic problems are caused by large differentials in speed. If traffic is flowing smoothly, faster vehichles in the left lanes, slower in the right, and no one is sharking their way through traffic, things will be fine. Doesnt matter if the fast lane is going 50 or 90. If people are yielding to faster traffic, signalling, and generally being smooth about things, traffic flows. Now, when you get people who just have to go 20 mph faster than traffic in the fast lane, and will go around anyone and anything to accomplish this, weaving, braking hard to avoid rear-ending someone then flooring it to speed up again, problems occur. Same thing happens when you've got people camped in the left lanes refusing to yield to faster traffic approaching from behind, or people braking unneccesarily. The two problems exacerbate eachother... and voila, you've got accidents and traffic. IMHO, if the police ticketed people who were wreaking having with traffic flow and creating dangerous situations (and it sounds like this guy could have fallen into that category, though bikes do make less of an imprint on traffic patterns than cars do), and didnt worry about arbitrary speed limits, things would improve on our roads.
Just my little rant.
Oh. I also think drivers training and getting a license should be harder. A lot harder.