An employee expecting, or indeed planning, to take a X months leave Y months after joining, with X > Y, isn't an irrelevant dimension. Especially if parental leave is paid, but I don't know if that is how the US handles leave.
An employee literally cannot be a high quality, productive worker if they are not working. Employers should not be forced to ignore relevant factors when hiring. That isn't fair on them.
And while you might see pregnancy as equivalent to having a medical condition there are actually a number of fairly important differences. For example, in the modern era, pregnancy is more controllable than illness. Quite a number of people enthusiastically plan on it. Those aspects, intent and control, are important for determining who should bear the cost. The cost should not settle on an unwitting employer looking for a new hire.
Fortunately this is exactly how it's implemented in most European countries: if the employee is not working the employer doesn't pay. The (usually state run) insurer does.
Requiring businesses to pay for someone taking time to care of their children is patently stupid and unjust and there is fully justified pushback against such laws.
But they are - that's the law. The same legal system that allows the corporation to exist at all and earn money in this environment requires them to ignore the fact that someone may be going on maternal leave and not discriminate based on it.
We the voters have decided that this is more important than the profits of any company, and in the end the voters (i.e. mostly employees) get to decide the rules of society, not the companies.
In the United States, there are many people who are in the reserve of the military, or in the National Guard. They often need to take some amount of time away from work for regular training and refresher sessions with the rest of their unit, in order to stay ready for wartime or domestic-emergency (since they also play a large role in responses to natural disasters) duty.
As a society, we've decided this is important enough to our future security to make it illegal to discriminate in hiring against someone who has obligations as a member of the reserves or National Guard, illegal to fire them for taking time away from work to fulfill those obligations, and illegal to force them to use their ordinary vacation time to cover that time away. And even if a reservist or Guard is called to extended active service, they have the right to return to their previous employer so long as that service does not exceed five years.
We've made that choice because, for each individual employer, the temptation is strong to let some other sucker hold a spot for a Guard or reservist, and not waste any of your business' money on them. Which is a tragedy of the commons situation.
Children are similarly an issue of security for our society. There is significantly less point to building things today, if nobody will be around tomorrow. So we, as a society, have also decided that employers cannot discriminate on the basis of choosing to have children.
You seem to have a problem with the second of these. Do you also have a problem with the first? If so, how do you find a consistent position that reaches those two different conclusions?
If your attitude is purely one of "don't use any of my money to do this", well, a government-run compensation system would be tax-funded and would use... some of your money. In fact, it would probably just be implemented similarly to employer payroll taxes, so it would mean you'd get to pay into it even if you somehow manage never to have an employee who has a child. Then you could complain about paying into a system that's not paying back out to you!
Or you could just learn to deal with the price of living in a civilized society, and accept that while this may be one specific benefit you'll never take advantage of, there are plenty of benefits you do get to take advantage of, that perhaps others don't, and that they pay into them regardless.
(and that's without considering that hiring and onboarding replacement employees is expensive, too, if your policy is to fire/not hire people who choose to have children, so please be sure to consider that as one of your costs)
Basically the same reasons you don’t invest in the 100% returns every year “investment opportunity”
And quite crying about down-votes.