It is ridiculous that we even have to make this tweet but:
Taehyung was with friends (who are not celebrities) during his private time and has to constantly manage multiple people asking for autographs, whether they’re fans or not. If he says yes to one, there will be people lining up for more and most of them will be resellers. This can cause major inconvenience to the entire restaurant and staff.
That’s why he kindly decided to leave an autograph at the end of his meal after making sure everyone was happy and safe. Stop trying to make a cute interaction that OP is so excited about into something negative, it is exhausting and unjustified.