Why are silencers illegal?

i own alot of guns, most of them are .223 and .308, and anyone who knows, .223s are loud, .308s, even louder. i live in an area where i can shoot my smaller rounds like 9mm .22, .17HMRs but the .308s start to annoy people after a while. i know you can't fully silence a .308 or .223 but you can make it quite enough were it doesn't bother people, and if i recall they were invented to shoot without bothering people, i could be wrong. i know the REAL reason there illegal, its about control, but what i want to know is what was the excuse to make them illegal? i can't think of any reason they would be, other then it gives us an advantage if we were to do something wrong (i have no intent to break the law or hurt people, i enjoy shooting for fun, its very relaxing to me)