This is probably a good time to make a broader point about the church and how it is defined. Of course, the theology of the church is a very immersive subject. Theologians could speak about it for days. The more salient points get lost, however, especially as they relate to political subjects.
The Church According To The State
As far as the Church Arson Prevention Act is concerned, a "church" must be multicultural. This is because the act is not so much interested in protecting "religious property" as it is in creating more hate crimes. The section reads:
"Whoever intentionally defaces, damages, or destroys any religious real property because of the race, color, or ethnic characteristics of any individual associated with that religious property, or attempts to do so, shall be punished as provided..."
Given the selective enforcement of hate crimes, it's pretty clear that this act was never intended to protect white churches, though a black or explicitly "multi-ethnic" church would qualify. Getting a definition of "church" from this particular law would be a waste of time.
The IRS, on the other hand, is VERY interested in your church. Over years of case law, the government agency has narrowed the definition of "church" to about 14 points. These include things like:
A distinct legal existence,
A formal code of doctrine and discipline,
An organization of ordained ministers,
Regular congregations, (etc...)
Given the incredibly loose definitions used by the IRS, almost any sort of formal organization could be considered a church. The definition is rendered useless by over-generalization and abstraction. There are no requirements for what you worship, how you worship, or that you even worship in any meaningful form. Whether it's a rural Baptist church or an urban feminist empowerment non-profit, the IRS can't tell the difference. But even after compiling case law for years, the federal agency can change its mind at a moment's notice. With a weaponized executive branch, your church could be labeled a for-profit political organization overnight.
Even if you are lucky enough to be ignored, some churches are better off not being a church. Given the selective enforcement of 501(c)(3) tax code, some churches are better off NOT being considered a church under the law (@Pro_Gun_Fred has written well on this subject: https://gab.com/Pro_Gun_Fred/posts/110865964091769346). A church can never be defined by generic phrases like "a place of worship" or "religious property." Even a public school would fit this definition. No, a church must be defined by what it worships.
No, Liberals Are Not Protestants
All too often, it feels like the Protestant label is used merely as a religious catch-all. Despite the fact that Protestantism has its own beliefs and ecumenical characteristics, everything from pluralists to paganists gets lumped in. For starters, Protestants believe that a church can be easily identified by the three marks:
the preaching of the Word,
the administration of the sacraments,
and church discipline.
Without all three of these signs, the church cannot be Protestant (or a church at all, for that matter). Right off the bat, it should be obvious that an LGBT+-affirming church does not practice church discipline. No doubt, the other marks would be in question as well, but the lack of church discipline is literally advertised on their website. As far as the mark test is concerned, this organization has failed.
Another hallmark of Protestantism is the commitment to the 5 solas of the Reformation. While it has been articulated in different ways at different times, the sola we are chiefly concerned with is Sola Scriptura - the centerpiece of Protestant ecclesiology. If a church does not recognize the Word of God as the sole and infallible authority for Christian faith and practice, it is not a Protestant church. Though our understanding may sometimes differ, recognizing all other authority as subordinate to God's Word binds Protestants together. So how does the UCC, an allegedly "Protestant" denomination, affirm sola scriptura by ordaining females? Hint: It doesn't. This politico-religious organization is anything but Christian, much less Protestant.
The state and other political interest groups have used ignorance to their advantage. Everything from mysticism to feminism has all been deemed "religion" in order to dilute definitions. A "church" could be anything. A "Protestant" could be anyone. But to the IRS (and anyone oblivious enough to play along), definitions only matter as far as you can weaponize them.