I guess you're being downvoted because people think this is obvious, but dragonflies won't get red eyes because they don't have red blood to reflect the light.
Red eyes are also caused by a particularity of vertebrate eyes, which have their blood supply in front of the retina.
This is also the reason why you can sometimes see moving dots when looking at a bright, blue-coloured thing like the sky: your eye sees the whole capillaries filled with red blood cells, but the brain processes them out because they're always there. The large white blood cells then appear as "less red" dots in the processed-out streams of red, and the brain interprets them as bright dots.
Insects have none of this, they don't have blood or blood vessels but a transparent haemolymph that doesn't really circulate through a complete circulatory system like us.
So there really is nothing in front of the insects' light sensors to reflect light.
Red eyes are also caused by a particularity of vertebrate eyes, which have their blood supply in front of the retina.
This is also the reason why you can sometimes see moving dots when looking at a bright, blue-coloured thing like the sky: your eye sees the whole capillaries filled with red blood cells, but the brain processes them out because they're always there. The large white blood cells then appear as "less red" dots in the processed-out streams of red, and the brain interprets them as bright dots.
Insects have none of this, they don't have blood or blood vessels but a transparent haemolymph that doesn't really circulate through a complete circulatory system like us.
So there really is nothing in front of the insects' light sensors to reflect light.