I have to agree with the above post that Maycomb's white population did not treat the First Purchase Church with any respect. Scout also mentions in the story that, during the week, the church was used for gambling purposes by white folks. We are not told if the church receives any financial payment for this use; we can only assume so. However, Scout notes that many of the newer tombstones at the adjacent cemetery are
... outlined with brightly colored glass and broken Coca-Cola bottles.
Although Scout seems to think the broken glass is both pretty and some sort of decorative motif established by the cemetery's patrons, the glass probably comes from the disrespectful white gamblers who desecrate the graves when they use the church on weekdays.
In Harper Lee's To Kill a Mockingbird, I do not find anything that says that the whites always treated First Purchase Church respectfully. This generalization might be far from accurate based upon the attitudes of many whites with regard to their attitudes toward their black servants, the black community in general, and Tom Robinson specifically.
There are two things that make me think that the whites simply steer clear of First Purchase Church. First, in Chapter Twelve, Lula's response gives the reader the sense that whites do not attend or go near the First Purchase Church. This church is strictly for blacks, as Lula points out.
"You ain't got no business bringin' white chillun here—they got their church, we got our'n. It is our church, ain't it, Miss Cal?"
It would seem that Lula is not the only one to feel this way. In Chapter Fourteen, Scout and Aunt Alexandra almost have an argument except that Atticus steps in and chides Scout for her disrespectful behavior. It starts when Scout relates to her father that she and Jem went to Calpurnia's church...
...Aunt Alexandra, who was sitting in a corner quietly sewing, put down her embroidery and stared at us.
"You were all coming back from Calpurnia's church that Sunday?"
Jem said, "Yessum, she took us."
Here Aunt Alexandra forbids Scout to visit Calpurnia at her house, and the incident of the visit to the black church gives Alexandra reason to speak to Atticus about letting Calpurnia go for the sake of the children, especially his daughter. However, Atticus has no problem with the children spending time with Calpurnia or going to her church. He clearly tells Alexandra that Calpurnia is like a part of the family and will remain with them until she chooses to leave.
Aunt Alexandra's attitude seems to represent the older southern families of property and long-standing in the community with regard to the separation of whites and blacks. In this situation we rely on drawing inferences, and perhaps conjecture, to come to a conclusion about how the whites treat the black church—with a great deal of "distance."