I could, perhaps, see them wanting to be cautious if you appear to be having an obvious mental health crisis (but even then, as a paramedic I've heard more than one tale of families ruined by the spending of someone who was unmedicated and bipolar).
I could even potentially see there being a law enforcement issue of creating a panic or riot, exaggerated for example: "I'm going to take this money and throw it on the tracks at a train station and people can see how much risk they're willing to take to get it".
But "you have to give us an acceptable reason"? No. I am of comfortable but not exorbitant means (lower six digit salary), and my cash withdrawal limit, by default, is $15K/day. And the one time I asked for that to be raised temporarily, the only questions I got were for an additional piece of identification, and that they were able to call the contact numbers they had for me on my account to verify that it was me who picked up the call. Not "for what purpose, sir?"
[0] https://www.bitsaboutmoney.com/archive/two-americas-one-bank...
Banks try to avoid holding excessive amounts of cash in suburban branches because it makes them attractive armed robbery targets. If you have a need for a large amount of cash, you can let them know (my bank says 24-48 hours in advance), go to multiple branches, or to a large city branch. Inconvenient, perhaps, though temporary. If it's for a business or a recurring need your bank is generally happy to make that part of their regular logistics, "Monday's cash delivery needs X because asimovDev regularly wants $50,000 in cash every Wednesday".
> it has to be approved
I'm not sure what you mean by this, but I don't think it's "approved" in the sense of the bank deciding if you're allowed to do so. But hmm: multiple ID checks, or a specific seniority of bank employee doing the check. Or if you decide you want to take out $250,000 and you have to do it in cash, they might a) want a day or two to physically acquire the cash, and/or b) have additional security due to their insurance policy. They certainly might try to suggest you look at a cashier's check or wire transfer or other instrument to do so. There's going to be a CAR for any transaction involving more than $10,000 in cash.
But I'd challenge the assertion that the bank tells you you're "not allowed" to withdraw "large amounts of cash" from an otherwise unencumbered bank account.