Tantawi calls for a ban on niqab

These images might help:

http://www.mykashmir.in/images/KTD/Activists%20of%20Dukhtaran-e-Millat%20march%20towards%20Eidgah%20on%20Sunday.JPG

When niqaabis are in prominence at these extremist gatherings (with no concern from the niqaabi-defending crowd), then yes, people have the right to be concerned.