That's too simple. Congress has to have something to do otherwise they wouldn't have their cushy jobs.
I’d rather have ability to file my own tax.
Who’s to say employers would do it properly, what recourse if not done properly and too much is taken?
It seems odd and un American (where we have say in things, liberty in ways other countries don;’t allow their citizens) for it to be a tax on the employees income, yet the employee doesn’t have major part in handling the payment of it and the possibility there are legal reasons people may owe more or less that have nothing to do with the employer - so why have the employer handle it?