There are two factors Bitcoin rises and fall:
1. There are big sharks that pumps/dumps money to make the prices of bitcoin/cryptocurrency goes up and down. Remember, sharks eat fishes. We call these sharks investors.
2. There are small fishes buy/sell/hold hoping to make some money. We call these fish gamblers.
If you buy a lot of bitcoins or any other cryptocurrency, and later decide to sell. Is that considered pumping/dumping? No it’s not! It’s investment. People that chases after these fast rising, easy money, and lose will cries foul or call them pump/dump! In a free market, you should be allow to buy and sell. You buy low and sell high to make money. Pump/Dump, Buy, Sell, and Hold is how you make money. This concept applies in any field from trading to manufacturing.
So.. are these ethical and legal? Yes they are. Here’s why…You are free to choose side: an investor, gambler, or stay away for making and loosing money investing in cryptocurrency.