To be fair to the M1A, that's not really the case. This is all the M-16 was ever originally designed to be.
No "fairness" about it. Both were designed to be just that. Its just one is much more adaptable to other uses and went down an ever expanding evolutionary road, while the other, quickly ended up in the reserves locker.
“The enemy is anybody who's going to get you killed, no matter which side he is on.”
― Joseph Heller, Catch-22