Cause you had already connected to Gemini. They made changes to the Gemini connection so as to allow people to reconnect Gemini, who were previously connected to Gemini on the same rewards profile before region unsupported started altogether.
Dear Brave Community,
In consultation with the team at Gemini, verifying Brave Rewards with Gemini will now be limited to Gemini accounts in the United States (US).
That is because of regulations.
In order to comply with current financial regulations (such as FinCEN and OFAC requirements, or equivalent regulators outside the United States), Brave Rewards payouts at this time must first go through a regulated custodian (like Uphold/Gemini).
Note that once you receive BAT into your custodial account, you can always withdraw it on-chain to your Brave Wallet.