Sorry, sounds like they've not been keeping the rules.
They are foreign dorm students who are allowed to remain on campus so long as they don't leave it. The Israeli capsule system allows for shared air so it's quite possible all 67 got infected in one Beit Midrash sitting from shared air.
They may have broken rules, but this can very well happen within the rules. It's also not that much of a problem in the short term provided they maintain the discipline and non of the 100 students goes back into the community. Everybody in there knew all along they have a high chance of getting infected.