The services offered by the lawyers you portray as being "good and necessary to the public" are also very lucrative and they are also offered by associates and partners at many large law firms. I used to write internet marketing copy for lawyers and I never met one who didn't salivate thinking about how to market to clients with "messy personal problems," or a legitimate case against contractors and insurance companies. For most personal injury lawyers, $15 a day for lunch would not be a great stretch. I'm not trying to belittle them - far from it. It's just that I think the services offered by corporate lawyers etc are in many ways just as essential as the ones you praise - if not on a personal level, then at least to the overall function of our economy.
Gross himself points out that this Chow for Charity thing is really meant for summer interns and not for the firm's actual associates and partners. These interns are students who don't have much money (law school is expensive) but who are nonetheless still interested in donating something somehow - in this instance, it's the tab for their lunch. What's actually bad about this? Gross never mentions how much (or even whether) the partners making $2.5 mil / year donate out of their own pockets. He also never explores any other charitable giving / pro bono services these firms offer - why would he, when this program taken out of context looks so deliciously damning, when it makes himself and his readers feel so morally superior to those rich lawyers everybody loves to hate?