It was not about individual fares though, as you have implied. It was about the territory of the two syndicates.
What I'm implying is that some taxi drivers in the area feel as if their backs are to the wall and are being very aggressive about fares they believe they're owed.
I don't allow myself to be cheated. However, I also don't simply hand over some money, turn my back, and leave when a taxista doesn't think it's enough. I owe him at least my reasons for not agreeing to pay what he claims the fare is.
Your advice is easy enough to give when you don't need to live with the consequences. We spend several months every year on the island. We have friends and neighbors who are honest taxistas. People know my wife's scooter and our house. There's no point inviting bitter feelings by acting in the immensely rude manner you advise.