In my opinion admin should not close any religious thread. Instead they should ban the members who misuse the privileges.
Let the healthy discussion go on. The truth will prevail. Muslims will never be untied until they debate and exchange knowledge in healthy environment. Those who are closing Islamic thread are the friends of Shaitan. May Allah give them the consequences in this world and the hereafter (Aameen).
For example, yesterday a member posted a thread advocating "Qabar Parasti". If the admin closes the thread and does not allow other members to educate through Quraan and Hadeeth that this act is SHIRK then the burden of those, who were inspired by the post and continue doing this SHIRK or start doing this SHIRK, will come on the admin, as they did not allow the truth or knowledge to be posted.
The creating group for Islamic thread did not work well. Let the Islamic discussion continue as before creation of groups.
Islam does not separate religion from politics. Only those members are against the Islamic debate who do not have any ground and they are just blindly following their Peers. They are afraid that the truth will shatter their Peer's empire.
The bottom line.... do not close Islamic threads but ban the members abusing it.