Hopefully primitive aliens will not be as hostile. But I do not know, that is something science will decide when we ever do find life.
If we are only slightly more advanced than them, I do not see the harm in contacting them, we are barely able to reach mars and the our moon. On star trek, they were a galactic civilization far more advanced. When they interfered with a primitive civilization it often had bad consequences and changed their natural course of evolution.
We are the sentinelese to advanced alien visiters. We shoot at their craft, we capture any living ones and cut them up for experiments.