It was a public event and it is against the law to discriminate against any orderly person with a valid ticket on the basis of religion. FOX News was also banned even after they showed press credentials.
Police threatened to arrest them for criminal trespassing. The venue was held at the Culwell Center, a taxpayer funded building. As such, designated terrorist group CAIR was in clear violation of the Culwell Centers Regulation 1.04 articulating the public cannot be denied access to this or any other event held there.
h/t Alan K