For the record, Sanger was opposed to abortion (called it an abominable practice). But she WAS an eugenicists and a racist by today’s standards. And she did support forced sterilizations.
Even Planned Parenthood hides the fact that Sanger did not advocate for abortion.
Sanger knew that early 20th century society would NEVER support abortion and she also knew that the support she enjoyed from prominent eugenicists would likely disappear if she promoted abortion. So, she pushed for forced sterilization because she believed that sterilizing "lesser" people would ultimately have the same result as abortion.
Keep in mind that she DID make these statements:
“More children from the fit, less from the unfit. That is the aim of birth control.”
“Birth control to create a race of thoroughbreds.”
“The kindest thing that a large family can do for its youngest member is to kill it.”