The only person you have any control over is yourself. When dealing/conversing with others, set a positive example, don’t assume bad intent, and grant the other person some grace.
When buying and selling it matters who you deal with. If it smells bad, it probably is so, move on. There will be other opportunities. Since this is your business, find your own balance between sales and risk. Consider your expectations and treatment of actual customers (who regularly purchase from you) vs. prospects.
When posting, if you have something to say then say it but, once is enough. Disagree respectively. If things deteriorate, step away. I would probably reserve the term brotherhood for my friends, but I certainly appreciate respect and maturity and I try to remember (not always successfully) that those qualities can start with me. At the end of the day, it’s just a stereo. Enjoy the music.