It's not just about KO. Yeah, KO is a shyt friend. It's also about Roman abusing his power and Sami don't feel right about that anymore, even more so that it's directed towards someone that deep down inside he still got love for. Jey freezing up and walking out ties into this- remember that Sami had to be the voice of reason many times when Roman turned his ire towards Jey.
Fair points but it's not like Zayn doesn't already know how Roman and the Bloodline gets down. Hell, he's participated.
I mean, let's look at it from a different perspective; would this be okay if a woman was trying to move on from an abusive partner of the past and because the partner has beef with the new partner he comes along to gaslight her into being conflicted up to the point she loses everything she worked toward with the new partner?
I get Roman and the Bloodline aren't exactly great people but they did treat him reasonably well. And once again, once Jey Uso was on his side he pretty much had the backing of everyone.....until Kevin Owens started planting those seeds of doubt which irritated Reign's paranoia. It could be argued that KO was more so looking out for himself and trying to create dissention within the Bloodline rather than concern for Sami Zayn, which is something Zayn should have considered.
I mean the fact that we are debating this means its a good story. I just think the inevitable KO reunion should have come after Reigns loses the titles, goes AWOL on the Bloodline and Sami steps up. It gives him more than just sympathy when the split happens, he would have credibility as well.