Greenway suggests that the Wobblies stumbled upon this modus operandi as a means of combating the street bands of the Salvation Army and the Volunteers of America, who frequently would drown out Wobbly speakers in a "cacophony of cornets and tamborines." One enterprising IWW organizer, wishing to combat the forces of obscurantist "pie in the sky" theology, "retired long enough to organize a brass band of his own.

Denisoff, R. S. (1970). The Religious Roots of the American Song of Persuasion. Western Folklore, 29(3), 175. doi:10.2307/1498356

Not OP, but I found this: https://en.wikipedia.org/wiki/The_Preacher_and_the_Slave

Of course any article can be biased, but this one has cited sources, at least. It would take further digging to determine if those sources are credible.

https://libcom.org/article/starvation-army-twelve-reasons-reject-salvation-army

In my opinion and based on my past reading on the subject, the simple fact that it’s a religious organization is enough to dissuade me from giving them anything. It is no small statistic that religious organizations are corrupt, hypocritical, expect obedience over tolerance, anti-union, anti-LGBTQ, ultra-conservative, and generally support the notion that people must be submissive to their authority.

I’ll continue to donate to secular organizations that do genuine good.

Off the top of my head, I can only think of primary sources. Would need to dive into some academic tools to find sufficient sources for Wikipedia's requirements. I'll make a note to do so, when I get the time to do so.