Unfortunately, the latest kollel scandal doesn't surprise me

It is an explicit gemara. The gemara in Kiddushin 30b states:

ר' יהודה אומר כל שאינו מלמדו אומנות מלמדו ליסטות ליסטות ס"ד אלא כאילו מלמדו ליסטות

My translation:
R' Yehuda said whoever doesn't teach his son a trade is teaching him to be a robber. [The Gemara asks] teaching him to be a robber? [The Gemara answers] it is as if he is teaching him to be a robber.

The Gemara states explicitly that if you don't teach your children to make a living they will eventually steal because they have no way of supporting themselves. Due to everything that is going on (financial crisis etc.) the Charedi population and institutions are in dire straights and need money. With no other alternatives to make money some turn to robbery exactly as the Gemara predicted.

There is another factor as well. When your whole chinuch is predicated on dismissing everyone else and saying that everyone else is worthless, wrong, a sinner, etc. it is very easy to justify stealing from them. After all, if the government is רשעים etc. there is nothing wrong with stealing from them.