Well, Tebow's demonstration is much more obvious. Had these symbols in Madonna's performance not been pointed out to me I wouldn't have noticed them at all. That could just be my naivete, but I would guess that there are plenty more out there like me who wouldn't have noticed the symbolism. On the other hand, everybody is familiar with Christian symbolism like the Jesus fish, kneeling to pray, pointing up at Heaven to thank God, etc. As far as why things are so dark and vile these days, I'm not quite sure about the reasoning for that. I would guess it's because it sells better than puppies and kittens. People like the theatrical, mystical aspect of that kind of stuff.
Maybe it's more obvious simply because you are familiar with Christian symbolism and you are not as familiar with occult / pagan / ancient egyptian symbolism?
I know we're speaking in generalities here, but if the mystical / pagan sells better than "puppies and kittens" perhaps we as a society are in more trouble than I would have thought or hoped. If you're right however, get ready for more...