Most students conclude that the first magazine, but not the second, was morally delinquent for publishing the advertisement. We aren't told why the students think this. We just know that the only information the students have about the magazines are their policies on publishing advertisements.

We know that both magazines published a highly offensive advertisement. For some reason, the students conclude that the first magazine was morally delinquent for this, while the second wasn't. They might be assuming that since the first magazine has a policy of reviewing advertisements to check if they are offensive, that magazine was delinquent either because it didn't find the advertisement offensive, or because it violated its principle by publishing it anyway. While the second magazine did not violate its principle by publishing an offensive advertisement, the students are also assuming that the principle of publishing any advertisement received from subscribers is not in itself morally delinquent.