In various geos in the world, there are various ways of addressing people and as long as no hurt is intended or expressed, it is fine.
I've travelled to the UK a few times and almost heard everyone addressing eachother as "dear" quite often.
In my particular case, I would have missed some business opportunities that were quite rewarding if I was sensitive about "dear" or "sir" or "madam".
In this modern connected world, we need to understand that not the whole world follows or can ever follow one standard protocol for general life situations.
As long as the other person intends no hurt or expresses no intention to hurt, "dear", "sir", "madam", etc are all fine. Wonderful opportunities may get missed if one is so sensitive to such general things.
There is "hurt" because it triggers some of us to not trust you since so many catfish use that word in their scam game.
This is a professional forum where we are doing business with each other.
Calling me "dear" is like calling me "honey".
That's not professional.