Every decision process is discriminatory, by definition.
But it doesn't discriminate on a prohibited basis (the decision to only bring in developers as novice interns itself; if the way you are choosing interns does, sure, that's a problem, but its orthogonal to the issue), so that's not a problem.
Things in the Constitution are not necessarily constitutional.
It is unconstitutional to have representation determined by land, not population. The structure of the US Senate would be unconstitutional were it not written into the Constitution as an exception.
There are some cases working their way through the system now. Can you prevent someone who is senior from taking a junior position? Have to see what the courts say.
But it doesn't discriminate on a prohibited basis (the decision to only bring in developers as novice interns itself; if the way you are choosing interns does, sure, that's a problem, but its orthogonal to the issue), so that's not a problem.