why are they attacking the anti-polio workers?

Re: why are they attacking the anti-polio workers?

During the hunt for Bin Ladin, a Pakistani doctor, Dr Shakeel Afridi, is alleged to have worked for the CIA. He allegedly organized a vaccination drive that enabled health care workers to access to the Bin Ladin compound, collecting DNA from Bin Ladin’s children and thus proving that Bin Ladin lived there.

Lots of alleged in there because, as per the nature of secret operations, actual solid evidence was never released publicly.