I think it's really easy for misconceptions of 'heavy music' or aggressive vocals to be associated with the whole satanic connection, but in the case of Chester, and how I read into his lyrics and message of the band, it couldn't be further from it...
Just listen to A Thousand Suns with the lyrics and that will instantly answer your question.
WTF?!! No way! have you heard the catalyst Mr. ??
No, Linkin Park isn't satanic. Though, some of their songs have back-masked messages, it still doesn't prove them satanic. Try listening to some of their songs, and you might understand what they're trying to say.
Again, I will say what they all are saying :]