I read the book awhile back myself. I'm actually surprised that anyone is actually surprised by any of this. Afterall, the Buddha himself spoke of such things.
You know what this is:
It's called SAMSARA!
There is NO organization on Earth, religious or otherwise, that isn't infected by this. Industry, the military, education, etc. As for "unserious" monks, that was one of the main reasons Ajaan Mun and the entire Thai Forest tradition STARTED! Read some of the biographies of the serious Thai Forest monks such as Maha Boowa, Ajaan Lee, Ajaan Fuang, Ajaan Chah, etc., etc. and pretty much to a man, they all stated that their first experiences in the Monastery's were with less-than-serious monks and that they had to seek out serious teachers of the Dhamma.
All institutions suffer from this. Lots of people get caught up in power, prestige and status. As has already been stated, look at the super-wealthy Christian preachers. Oh yeah, they are REALLY emulating Jesus...NOT! This doesn't mean that there aren't good and serious Christians, because there are. I was raised Catholic and actually met some very fine priests and nuns...I also met some real stinkers.
As far as scandals, I think that the Mahayana Tibetan's have had more than their share. Again, there are some wonderful Tibetan teachers...there are also some really serious sexual perverts and drunks in these groups ("crazy wisdom" be damned.) We cannot judge an entire group of people or religious teachings based on the misdeeds of a few.
Having said all this, there is ONE person that we can work on and one person ONLY: Ourselves. Whenever I read stories such as these, I just want to redouble my effort to get out of Samsara.
Oh, and one final thing. Ven. Dhammika is wrong about: the lack of anomalous phenomena in spiritual practices. Just because HE hasn't personally experienced them doesn't mean they don't occur. I've experienced them personally, I KNOW they are real.