There is a big difference between investing in bitcoin and day/swing trading bitcoin. If you invest some money and forget about it, that's one thing. If you constantly try to ride the wave of bitcoin's price and try to multiply your money a few times a day or week, that involves so much more risk, one bad call can ruin it all. The latter is gambling.
Your explanation is make sense. Daily traders, people who buy and sell bitcoin in daily basis can be considered as gambler. Tbh, in our daily life, there are a bunch of things that can be called as gambling as well. But, as long as it is legal, we shouldn't worry too much.
I'm sure there are many day traders who try their best to analyze bitcoin's price path, and they may luck out often, but the bottom line is it will be impossible to predict bitcoin's price 100% of the time. If someone can ride the waves, good for them, but emotions can easily get in the way and ruin everything.
Yes, many things can be considered a gamble. Some people gamble with their freedom when they commit illegal acts to make money (robbery, selling drugs, etc). That's a totally different topic though
Aside from that , trading depends on the outside factor such as news, development, hype, FUD etc, while gambling only depends on its internal setup and is driven by chance. This means the risk involved in trading can be manage, mitigated or nullified if the person doing the trade is skilled while gambling , we just rely on chance and risk is fixed and cannot be mitigated.
