haha. I get it.
Some do like to slang it that way like as if they were saying it. Same goes with "broda", or whatever the heck way they want to slang and be cool with. It all means "brother".
It's a friendlier way to address than "dude" or "man". It's a friendlier word and it brings a friendlier vibe, like the other person is better than just a stranger. That's a good thing. And when it's a good thing, some want to continue it. So that's what they do. Also influence. But there's nothing cultural about it.
Im a FH keeper. I do say bro when I feel like it. Nothing wrong with that.
So if youre lost in the middle of nowhere and do not know what "bro" means, which is pretty strange, it means brother. And there's nothing to it but friendliness and it's a word used by many in the cities.
I just reread the title. For example. "hey FH brothers" would sound friendlier and closer than "Hey FH guys". It's just a better meaning. Just like down south, talk different from up north. An influence of who you around too.
And I see some make it seem like funny. Maybe just need better understanding.
i use the term bro or brother to refer to people as my brotherman. within this hobby there are many different races of people, and to be friendly to all in a common way bro or brother is universal in my eyes.
I read a Singapore arowana site every so often and they all refer to each other as "bro" and "sis". Brudder is also popular and other variations (as you stated) as well. Those guys know their flowerhorns and have some amazing fish and tank set ups.