This is unacceptable because they have no problem with showing their face in the office instead of concealing it behind a veil.
These people need to be reminded that to be inclusive with this team member, they need to turn their camera on.
I remember one job interview I had, I had my camera on, and the two people interviewing me had theirs off. Difficult situation for me because it makes a difference in communication being able to see the person, and also, a job interview is especially difficult because one wishes to not upset the interviewer. But in retrospect, I think if this situation occurred again I would speak up and ask if it would be possible for them to turn on the camera.
Camera being on or off in meetings can be passive-aggressiveness.