I can see two things that can be done here which do not put you directly in the firing line, and should therefore be actions you can take which would not necessarily interfere with your advocacy for DS:
1) Use it as a teachable moment to DS. In age-and-maturity-appropriate terms, explain what the lyrics mean to you, and why you feel them to be problematic.
2) Reach out to other parents and ask them if they're okay with this. With any luck, someone else will reach the appropriate level of outrage, rally the troops, and lead the fight. This really should be a multi-parent effort anyway. They shouldn't be hearing it from just one.
And if you get the general sense that nobody wants to do anything about it, that tells you something about the community culture, likely to be shared by the school staff, and you'd be unlikely to have any success advocating against this. In that case, you'd be smart to choose the battle that is most important to you: DS.
