First, I view humankind as swimming or existing in a big ocean. Like fish, humans swim in groups. I exclude myself from the pools of people who are exploitative, liars, thieves, etc. I only have anything to do with people who I consider at the same level of integrity as I. Those are the only people who count to me and I don't pay much--if any--attention to the people in the other groups.
So it doesn't bother me that they do things like what your friend says:
bad reviews from people who don't care for me, my methods, or because I don't play the "with us or against us" game in gardening cliques (of which there are many).
She also shared how much effort will go in to stealing the images in my website, distort my stories - whatever it takes to cut me down and elevate themselves.
The one thing I might do is see if criticism might be valid and thus make me better.
If a person copied my stuff, I would just feel sorry for them for cutting themselves out of the creative process.
I think your friend did you a favor in tipping you off to what could happen. It gives you plenty of time to construct a mindframe that will keep you from too much aggravation.
Anyway, if you take anything from this at all, it's to try swimming with your own and removing yourselves from the ones who aren't there yet. They'll eventually get there, but I don't think you necessarily have to be involved in it.

Cher
and p.s. re the vendor who asked you to make the purchase, a republican would say "that's how the free market is supposed to work."