If you get money from several different entities, how do you prove which money goes where? To me, it seems impossible because it all goes under one umbrella.<quoted text>
Abortions represent only 3 percent of total services provided by Planned Parenthood. Republicans would deny the funds for the other 97% of Planned Parenthood's activities to punish them for offering that service to their clients. Even though (as you admit) they are prevented from using the federal money they receive to provide abortions.
Let me put it another way: If our federal government was funding a right leaning charity organization that helped out the poor, bought clothing and so on, but part of their spending went to help the Catholic churches in the area, would you accept their claim that no government money went into those churches?
I bet the left would be on the Republicans like white on rice and the ACLU right behind them.