There are only a few people in a company that really care about profit/loss and have influence on it. Most just try to survive in the political environment and some of them get a power trip on the way.

Shockingly not all people in a company are about the bottom line. Perceived power is worth more to many.

Well the managers are human and not perfectly rational, plus corruption is also a factor as well - doing it for their own purposes. If they were we wouldn't see systemic hiring discrimination - they would be fools to pass up undervalued labor. Instead they use their position to push their own values over money. Unfortunately own values often includes petty authoritarianism where they would rather go unquestioned than do things right.