A Simple Case of Racism?

Interesting piece in the Haaretz weekend magazine about the Yeshiva community of Lakewood, New Jersey. The article starts off by calling Lakewood the "new epicenter of ultra-Orthodox life in the United States", and noting that it is "the largest yeshiva in the world today". Good description of the Lakewood style of learning, or the "habura paradigm", as it is put:

The great majority of the world's yeshivas concentrate on a handful of tractates known as "the Yeshivishe mesechtas" that raise theoretical issues around which much of the Lithuanian style of Talmud study revolves, but Lakewood has moved well beyond this model. At any one time, just about every section of the Talmud and Codes is being intensely studied by one of the 173 haburas operating in Lakewood.

The habura paradigm is a product of the decentralization of authority, at least within the confines of Talmud study, that is one of the signature marks of the Lakewood revolution.

The article also makes mention of two recent issues that have come up in the community. One is the recent banning of books by the Yeshiva leadership. The article makes mention of three such recent incidents, most notably, of course, the banning of books written by the "Zoo Rabbi", Rabbi Nosson Slifkin, whose plight has become a bit of a blogosphere cause celebre. (Most notably here and here).
The other issue mentioned, and one that is a very real one in Orthodox communities the world over, is the increase of teens "at risk", or in rebellion from the strict upbringing that is the norm in Lakewood. Apparently, more Lakewood teens are turning to drugs and alcohol than ever before. The article outlines a few attempts some in the community have made in dealing with the problem, such as:

The Minyan, a gathering place for marginal Lakewood teenagers where they can come to pray, hear a Torah class, or hang out - even if they are wearing jeans and have a tattoo on their forearm.

But these attempts at helping such disaffected youths seem few and far between. What bothers me most is the fact that the prevailing attitute in Lakewood seems to be how to prevent the "good kids" from being affected by the "bad kids" instead of looking for preventative measures or more programs to deal with those already affected teens. One line of the article I found particularly troubling was this:

The answer for many of the schools has been to become even more selective. Dozens of prospective high school students, boys and girls, have been left stranded, without a school this year, and even gentile real estate agents have begun warning house-hunters that they'd better line up a school for their children before they buy in the community. And some of the prejudices that have haunted the Israeli Haredi world are finally hitting Lakewood - one prominent high school for girls which for years admitted students of Mizrahi (Middle Eastern) origin has now changed its policy and announced it will admit only Ashkenazim.

What??? Can someone enlighten me as to why barring Sefardi students from Lakewood Yeshivas will in any way prevent troubled teens from straying? I live in a neighborhood that has more than its fair share of "wayward teens", and I can tell you that they are not limited by any stretch to coming from families of one descent or another. Can anyone shed some light on this policy, both the veracity of its existence and the line of reasoning that led its creation?