Because PP provides other medical services such as cancer screening to poor women.
PP maintains that their abortion services are funded totally by the private money and the public money goes only to provide the other medical services.
But the anti abortion group says that the private and public money is fungible, and because they are receiving the public money for other medical services, their ability to provide abortions is enhanced.
So, in states such as Texas, the state money given to PP for other medical services was cut off and instead given to womens clinics that didn't do abortions.
In response PP said the two missions are inseparable and because Texas redirected the money, the poor women of Texas are getting far less other medical services.
I don't have any first hand knowledge of these issues but I think that many think that there are affluent women who use PP's services only because they don't encounter judgementalism at PP and PP is very discrete.
Thanks