Thank you Y.W. Editor for your link highlighting the behaviour of wayward bochurim in Jerusalem.
As a parent of a yeshiva student I feel strongly this is not about yeshivas taking in students without proper care and responsible guidance, this is also about young men with too many hours in the day and night to mess about with and get into trouble.
If you are able to afford to send your children away from home to study Torah consider what is truly proper Torah study, is there time for chesed, helping the poor and disabled in Jerusalem, if not, why not? Is there time to teach English, sport or music to poor and disadvantaged children, if not, why not? If there is proper use of time for Torah study with all hours used appropriately for study and play then why is there time to riot and misbehave.
There is a terrible risk of young boys getting radicalised beyond their parents understanding, learning not to feel part of klal yisrael, but part of an imaginary superior sect far removed from Torah true values, able to act as they please with mentors and teachers failing to do their duty.