[M T]

Didn’t the WHO also state at the beginning that masks do not help?

I believe that neither WHO nor CDC said a mask did not help.

Instead the CDC said that they "did not recommend" wearing a mask unless you were infected, or you were caring for an infected person.

CDC FAQ from March 31:
"CDC does not recommend that people who are well wear a facemask to protect themselves from respiratory illnesses, including COVID-19. You should only wear a mask if a healthcare professional recommends it. A facemask should be used by people who have COVID-19 and are showing symptoms. This is to protect others from the risk of getting infected. The use of facemasks also is crucial for health workers and other people who are taking care of someone infected with COVID-19 in close settings (at home or in a health care facility)."

For a WHO poster, see BC's post from March 29.

[M T]

Didn’t the WHO also state at the beginning that masks do not help?

I believe that neither WHO nor CDC said a mask did not help.

Instead the CDC said that they "did not recommend" wearing a mask unless you were infected, or you were caring for an infected person.

CDC FAQ from March 31:
"CDC does not recommend that people who are well wear a facemask to protect themselves from respiratory illnesses, including COVID-19. You should only wear a mask if a healthcare professional recommends it. A facemask should be used by people who have COVID-19 and are showing symptoms. This is to protect others from the risk of getting infected. The use of facemasks also is crucial for health workers and other people who are taking care of someone infected with COVID-19 in close settings (at home or in a health care facility)."

For a WHO poster, see BC's post from March 29.