The question here is surely what is it that makes something stated to be a religion worthy of being treated differently from any other beliefs. First of all you have to establish that any religion merits this, and what type of treatment is merited, then how you establish that what a religion means so that the treatment is consistent.
It doesn't seem to make any sense that because you find the actions of those following a religion to be ludicrous that this means it isn't a religion since by that process there are no religions. Further to use the supposed motivation from those involved as not being serious enough is fraught with the same issues.
It has always looked to me that people use the word cult to describe religions they don't think live up to some unclear standard that they have in one of those verb declensions:
I am religious
You are cults
They will burn in the lake of fire.