If you need ten dollars for food and cigarettes, and you only have five dollars, you are going to have to go without something. Probably cigarettes, since food is a necessity. It depends how powerful your addiction to abortions cigarettes is.
If I give you five dollars and say, "You can only spend this on women's health services food", you now have ten dollars (your five dollars and the five dollars I gave you) and are able to buy food AND cigarettes.
So my five dollars, even though earmarked for food, helped you buy cigarettes.
Just so with federal funding of Planned Parenthood. It enables them to perform abortions.
Money is fungible.
If I "defunded" you and took my five dollars back, you would get this fungibility principle the moment your nicotine withdrawals kicked in and you had to decide between buying food or cigarettes. You could no longer buy both.
Take away PP's federal funding, and they will have to decide between abortions and women's health services.