It's frustrating but if they are trying to be complaint with some regulatory authorities and not be closed down they have to have some KYC, anti-money laundering and anti-terrorist financing rules.

I know you as someone trading on a personal level won't be using the proceeds of illegal weapons trades or whatever but they are still obliged to ask you.

I have some KYC'd investments & sports gambling, crypto and online bank accounts. They basically all have the same requirements to withdraw. As a rule I'd KYC before depositing so then I can withdraw with ease.

KYC, and source of funds questions are required by law. Trust me if companies could legally avoid it many would as they could get way more customers and have way fewer staff. I work in Investor services at a mutual fund and getting the kyc stuff answered correctly is annoying but needed so that our company is complaint.