They are killing machines, from both the way the throttle turning/speed/cornering/overtaking is addictive, and the way they are poorly seen by other road users
There's been a lot of judgemental and generalising twaddle in this thread which, if directed towards cyclists on, say, a sports car forum, would have us up in arms. Bloody dangerous cyclists, they all jump red lights, ride recklessly on the pavement knocking old ladies over, never have lights at night, etc.
There are bikers and bikers. Most are responsible, many get significant amounts of extra training over and above the legal requirement, ride considerately, make efforts to be conspicuous and have sufficient skill to keep themselves safe.
There are many more car drivers who use excessive speed in hazardous areas than bikers, and many, many more people die at the hands of car drivers than bikers.
The fact that the rider is vulnerable leads most to develop a keen sense of self preservation and most don't succumb to the race-track-on-the-the road culture which leads to the sort of antisocial and dangerous riding that has been extrapolated by some here to encompass the whole motorcycling community.
Yes, there is a subset of bikers who think they're safe dashing round at high speed despite the fact they've never received any training to do it, save for the odd track day learning to get their knee down, but they certainly don't represent the majority. They are the noisiest and most noticeable, of course, but that doesn't mean they prevail.
Bikes are a quick and efficient way of getting one person around, particularly in congested areas at busy times. Provided they are used responsibly they have a lot to offer in terms of reducing congestion, pollution and emissions for those that can't cycle.
And can we please drop the ignorant generalising prejudice. We can do better than that here.