What is the point? either you construct it in secret and hope the secret is safe (no spys!), or you construct it in public so the enemy already knows where it is. In the first place you hope the enemy doesn't know. In the second place you know the enemy already knows so you mitigate that by either having so many that the enemy cannot deal with them all, and/or you mitigate by making the strong enough to withstand an attack.

These didn't have anything rational about them. They are literally everywhere- seemingly randomly placed in the middle of farm fields, etc. and they kept people busy and were a response to the ever present "threat" of the US and/or USSRs ever imminent attack. So camouflage didn't matter.