“the means of getting there might open the door to greater evil.”
Depends on whether you think they are stopping child abuse, or trying to stop a religion, doesn’t it?
Nothing illegal has been done so far in pursuing the child abuse/ sex with a minor aspect of the case.
IANAL, but I think it's preposterous to believe that the Fourth Amendment was written so poorly that it didn't mean that the required "Oath or affirmation" was that an actual crime was committed or imminent. The idea that mere hearsay (that wouldn't be admissible in court) would be enough to meet a Constitutional requirement is absolutely ridiculous.
Further, that a Texas Ranger would pusue a warrant without even so much as minimal due diligence is a sickening thought as to how far we've fallen.
I don't believe that the authorities' motive alone determines whether a path to greater evil is open. I believe that the way to hell is paved with good intentions.