I may be wrong, but I thought Russell's comment about "lack of character" was directed at Roxy's inability to handle the constant rain that came before the sunshine she was enjoying on the beach. She was miserable and let everyone know it. Everyone was in the same boat, but she obviously didn't handle it as well as others. I don't believe he was saying her reliance on God and prayer showed a lack of character.
I thought Denise was very respectful in her comments as well. She just said that while Roxy relied on prayer and belief to gain strength, she found her strength within herself. I didn't see anyone being disrespectful or hypocritical.
Now, as for me, I admit I was a little confused about the speaking in tongues on the beach. I know that wasn't Latin, so I can only guess that's what she was doing. Is it something that goes along with prayer for certain faiths? I was confused and certainly if I were Denise and Russell I would have been confused if she were doing that sitting just a few feet away from me. But, to each his own, and if that gives her strength then that's great.
I personally think Roxy got the boot because obviously she is a miserable human being in general. She didn't appear to have a funny bone in her body, and her reaction to Bobby Trap's comment that it was cold enough she would have snuggled with Roxy to get warm if she could have (a shudder and a 'no THANK you' body language) said she may have other issues to deal with. I think she is hugely judgmental and appears to be very rigid in her world view. She would have had issues no matter what on this show, I think, because she was unable to hide her disgust or her judgments. A big part of strategy in this game is to get along, and I don't think she would have been capable of it.