> They also got me reported to HR by the manager of the XROS effort for supposedly making his team members feel bad

Sigh... Usual company politics.

No matter how much money you pour with top talents, code quality, documents etc, developing a custom OS doesn't make sense.

Been there, seen that. I faced a similar situation at one company. They failed on custom Not-Invented-Here syndrome derived implementation. My technically correct skepticism was criticized for decreasing moral of the team working on it.