Let's be pragmatic for those who sees gambling as same thing with trading;
Gambling is always betwixt two opinion, whether it's positive for you as profit or negative to you as losses. This directions cannot be measured to which side it will fall. This has a straight line, which is either in or out, having no certain direction.
The above stated terms has a little similarities with trading as well, but the difference is that trading has tools which with good knowledge on how the tools function, you can determine which direction will yield profits. It also has a tool in which can help secure your profit, when there's profit available, so as to avoid total losses when the market turns around.
Everyone is free with their opinion, but it's so blur when one says gambling is same as trading.