Bellamy is an amazing character, someone extremely human. Remember that we are in a post-apocalyptic world in The 100. Wars for survival are inevitable. Bellamy is like Clarke. He trusts grounders. But don't forget what psychological state he was in season 3.

Pike saw the emotional state he was in after Gina’s death and I think Gina’s death was too many. I said it before, but Bellamy is a traumatized and distraught man in season 3. He doesn't know where he is.

He always regretted following Pike and participating in the massacre of these grounder soldiers. He realized he was on the wrong track, but what could he do ? He was in Pike's influence and had no one to support him. He was alone.

Stop presenting Bellamy as if he alone killed 300 grounders. Remember, he spared Idra. It is thanks to him that she is still alive. It shows that his real him disapproved of Pike. He wasn’t himself.

I love Bellamy with all my heart. I disapprove of his choice to have followed Pike and to have participated in this massacre but I do not forget the emotional state in which he was.