Shorthand for "if I understand correctly". Like IIRC, (if I recall correctly) and a bunch of others.
If they picket the little girls funeral, then someone needs to buy a truckload of manure, and put that where these lowlifes are picketing.
And to address your original question a little better:
Most if not all and I really believe "all" Baptist churches are autonomous, they may be affiliated with a particular convention, as mine is with the S.B.C. but he S.B.C. does not have any say in how individual churches are run. The S.B.C. can and does "disaffiliate" from churches they might find to be heretical and/or like the Westboro Baptist Church but as far as I know the W.B.C. never was connected in any way to any convention.
The primary purpose of the S.B.C. is that they fund missionaries through many small churches (affiliates) sending money to them for that purpose. The S.B.C. also provides literature for teaching purposes, to those who want to buy it.
Fred Phelps and his crew are no more Baptist, than I am Muslim.