They've both messed up - Roxanne Pallett I think is far more 'dangerous' having form for these kinds of accusations and also that weird thing where she fell in the pool with Hardeep without him even touching her. Did anyone see that? So utterly bizarre.
I don't think there's any coming back for her to be honest, in terms of any kind of show business career. She also seems to have no support from any source apart from direct family and partner - even former co-stars don't have a good word to say about her.
Coleen Nolan on the other hand, whilst culpable ... was part of a set up which involved producers, her own sister and indeed her co-hosts on LW. I think in her case, there's a lot more pent up dislike of her due to perceived smugness, past comments and so on. If she takes a sabbatical for a while, I think she can come back from this. Public opinion is also far more divided - as evidenced by this thread.
If they are receiving death threats and so on via social media, there is no excuse or justification for it, but sadly we know, there are some sick people trolling the internet, and they won't be the first, nor the last, celebrities to receive such comments.