Lastman, while i see what you are driving at, its a tenuious thread at best.
Lets look at the case if jimmy swaggert. The wt filed “ “amicus curiae”, which definition is found here :https://www.merriam-webster.com/dictionary/amicus%20curiae#legalDictionary. It did not mean then or now that the wt was a “friend” of jimmy swaggert, rather, legally they had common interests. Its also noteworthy that jimmy didn’t ask the wt to file said brief nor did the wt offer on his behalf. It was offered on behalf of the wt’s position.
Amicus Curiae is a process where a person or entity can comment on a case if they believe the ruling in said case will have an impact on that person or entities interests. In short, the wt knew an unfavorable ruing against swaggert would directly impact them and filed their brief. The brief didnt make the wt and jimmy swaggert ministries friends, allies, business partners or even cousins.
This situation you cite is exactly the same. This organization is exercising their legal right to comment to the court on a case that they believe will have an impact on their organization if an unfavorable ruling is handed down to the wt. It dosent imply or establish any sort of relationship between the parties beyond a common legal standing, in this case organized religions.