Steve Rogers is responsible for trillions of deaths

The willingness to sacrifice one's own life is entirely different than deciding to sacrifice someone else's life - even if the sacrificial party agrees to it. Vision could have just chosen to end his own life. Steve Rogers has never elected to sacrifice one individual for the sake of the majority. To the contrary, he has always placed a premium on the life of the individual such as in the case of one James Buchanan "Bucky" Barnes. His decision not to kill, or allow the Vision to kill himself, is consistent with previous portrayals of the character.

Vision is not a cyborg. In the MCU he is an Android.