It's only wasted money if you believe the aim was actually to help anyone in Africa. The real aim was purely political.
tl;dr: PERPAR has cost nearly ~$50B all together. The abstinence aspect may have jelled nicely with how the Bush administration sees the world, but it certainly also would have been a "sweetener" in getting a Republican-controlled Congress to approve so much foreign aid for non-terrorism-related purposes during Bush's terms.
edit: oops, posted the excerpt from the link rather than the link itself.