And once again you are wrong.
Blue is NOT the most dominant colour in the spectrum. The lightspectrum does not have dominant colours. It has wavelengths. For that matter, it has no dominant wavelengths either.
The sky is only blue when it's clear, during the day with the sun shining. It's obviously red during sunset and dawn, grey when overcast, etc etc.
Space is black because there is nothing to reflect the light. Being colourless also becomes a colour, like being heat-less becomes cold.