Because they were the most well known of the affected companies and they didn't really do much to repair the goodwill the issue cost them.

Sure, they "put up $300 million for repairs" according to https://www.theguardian.com/technology/blog/2010/jun/29/dell..., but I bet the lions share of that went to their largest purchasers, so the people who blew their school's IT budget on Dell computers were just SOL.