The lawyer is lying. Lawyers aren't mandated to do pro-bono work. In one state, New York, law students applying for the bar have to do 50 hrs of pro bono work. This is a one time requirement. On top of it, you aren't required to do actual charity... you can do your 50 hrs promoting abortion at Planned Parenthood or NARAL.
I got into a huge argument in class because I said compelling someone to do charity defeats the purpose of charity. And I'd much rather continue to volunteer doing non-legal stuff, which actually helps out the community, rather than some liberal douche who puts in 50 hrs helping women secure late term abortions.