Some people may talk like that, but I think trading and gambling are very different. Trades have an agreed consensus analysis even though they already have an agreement that takes the form of a sell or buy order. So they have agreed and it is very different from gambling. Gambling or betting is usually only armed with a lucky guess. So trading is not gambling, but it can be trading into gambling because it does without analysis and only based on guesses.
Trading and gambling are likely to be seen as the same because both have high risks. But if you are a pro trader, your trading may likely to be more profitable than seeing it fall on gambling. The only reason you think trading is gambling because you trade without knowledge and preparation, pushing you to trade without good market analysis. In the end, trading looks like gambling since you fall onto losses rather than gaining profits. However, with gambling, no matter how good you are in that certain game, gambling will always be luck based and pure guesses.