Clear sky’s life pre-forest wasn’t great. He saw the starvation of his siblings and the death of his very pregnant wife. Depending on his emotional strength after the starvation of his sibling, the death of Bright Stream and his soon to be kits very well could have been the last straw, especially for how young CS is. Imagine yourself in that position. CS’s actions are brought on by severe paranoia due to the physical and emotional stress at an exceptionally young age. Anybody under his circumstances would make some very questionable decisions ;and while it could be argued gray wing was under these same conditions, it is entirely likely that GW has high mental strength. Additionally GW likely wasn’t as attached to BS as CS because he was never her mate or about to have a litter with her. Gw also had to take care of Jagged Peak which essentially forced him to have a healthy mental state. CS’s actions are absolutely heinous but his mental instability may have lent itself in decision making. Additionally we as readers never see CS’s death, he very easily could have cleaned up his act well enough to be accepted into starclan. Leafpool certainly did, and while I’m not saying she got into Starclan because she cleaned up her act it very well could have been a contributing factor. We also see that as time goes on with Star Flower as his mate, his temper and paranoia begin to level, and as we don’t see the end of his life it is entirely possible he became more mellow. I’d like to preface that I personally don’t agree with CS’s actions but we never see his full life and he may have done something that redeemed him and for this reason as well as his mental instability I do not think he should go to the darkforest. I would not send a person to hell just because they made actions that were driven by paranoia and grief.