It's semantics. I say there are no professional gamblers. There are professional poker players, professional black jack players, professional sports bettors and so on, but what they do they don't consider gambling. They consider it taking advantage of their edge.
Trading is gambling for people who do not understand trading. Gambling is connected with lack of knowledge. Knowlegde can turn gambling into trading.
Even good ol' volpri had to admit painfully just a couple days back that trading had an element of gambling. I spat out my Weeties when I read that.
Depending on the definition of "gambling" the outcome can be different: gambling is anything that is not for 100% predictable: then trading is gambling gambling is anything that is with high probability predictable: then trading is not gambling My ex wife now fully understands the difference. When we were married she said that I was a gambler. I was in the beginning struggling but things went better and better so I made good money. My ex wife did not have to work, had an own car, a gardener and a cleaning woman while we were married. After we divorced she had to go to work full time in an elderly home washing people. I moved after some time to the Italian Riviera with my new wife. My ex now understands that her definition of gambling/trading was not right. The result is that she is working full time and my new wife is lying in the Italian sun. My ex gambled wrong.