You get profiled when you sign up for unlocking a xiaomi.
In order to use the official windows-only tool:
You make a xiaomi account, wait a month or more, then put an internet connected sim card that receives an sms verification and try to unlock, if it fails, you wait a day to try again.
You can unlock about 3 devices at most every 6 months with one account.
They found a balance that is easy enough for tech saavy users, but not too easy for the general population. Helping someone with his phone is a chore if you aren't charging money for it.
Xda forums is much less interested in developing unlocking for xiaomis since there is this official method, and I can't blame them.