They can, in the evening. Red and amber light contain very little blue light, so they're the least disruptive to melatonin, which is why a dim red or warm lamp at night is gentler on your body clock than bright white light. Some people use warm or red night lights for exactly this reason.
Just don't expect red light to be a sleep aid on its own, it simply avoids the alerting effect that bright, blue-rich light has. Pair dim warm lighting with a screen curfew (or amber glasses for late screens) and a dark bedroom, and you've got the light side of good sleep covered.
