Trading is indeed a gambling since you are risking money to earn money but this kind of gambling is different from other gambling games we know since trading could be learned and theres a proper way on how to lessen the risk and increasing the chance on making money on long term basis which you cant found in any gambling game,This is just my own view.
If you really think risk involved in trading is sitting on the same level as gambling, then you're simply not a trader, or at least, not a good one.
Very simple example;
Gambling - You dice $1000 worth of BTC at >50.50 where the outcome is <30.50 ~ Result $1000 instant loss.
Trading - You place a trade $1000 worth of BTC where you buy at $900, and where you end up selling at $810 ~ Result 10% = $100 loss.
In the trading example you then still have $900 left that you can use to trade your way up to the green again, where with gambling you end up with nothing. I can't deny that trading doesn't involve some sort of luck, but that's minimal where it's the skills that lead to you making profits. Gambling in this case is pure gambling where skills can't be applied.