I think the Brother situation clearly highlighted the cleavage in culture differences, that we are all being part of as active users of Fiverr.
Yes, I too have been called “Bro” many times, facepalm.
The thing is that as @looseink genuinely mentioned : he is not his brother. Which means from where he comes from, it’s weird/inappropriate to be called in such way. @homebrew_dude if it is hard for you to understand such international standards, you might run into troubles dealing with clients by not accepting this reality. And there was no hostility into his answer.
So yes, as an advice, avoiding Bros / Sis / My dear / Mam / etc. in a professional environment is highly preferable. For everyone’s sake. This is not a Jake Paul’s YouTube video we’re all into. God dammit
If you don’t know who Jake Paul is make yourself a favor and DO NOT watch any of his videos, your life is beautiful right now.