1. I am a bounty hunter, I join bounty campaigns to support projects: I share information with everyone. Thanks to a good marketing strategy, the project had a successful Token-Sale & reached softcap. But in the end it was just a scam project, the team disappeared with tens of millions of dollars from investors.
Am I involved in a crime that makes investors lost money?
Only if you kept on promoting with prior knowledge that the team plans to exit or if it's blatantly obvious it's a scam.
2. I am a team member that develops a potential crypto project. I have mobilized enough softcap to realize my idea. But in the end, my product failed to meet the market demand, the token price dropped 100 times and was delisted from exchanges. Many holders lost money. A holder committed suicide.
Was I the cause of his death?
Nah. There's a burden of guilt if you were not transparent from the beginning that investing in the project poses risks and that you made a promise of guaranteed profit.
3. I am a trader. I make a lot of money from trading. But we all know that the total profit in trading is < 0 because when one person makes a profit, another will lose money, and must pay transaction fee to exchange. So when I am happy and have profit of $1K, someone is sad because he has lost $1K.
Should I rejoice over other people's sorrows?
I don't see any problem with rejoicing because you made a profit. You might as well blame the whole market when the coin/token that he bought lost value.
Let's change the story a bit, imagine if you bought a pair of shoes at $50 and then sold it at $75. A month later the market value declined because new models were released. Will you feel bad?
4. I am a crypto fan. I often share market news on Facebook. A friend of mine read and entered the crypto market himself. In the end he invested in a scam, he lost all his property and his wife and children had a difficult life.
I felt very miserable when I met his wife and children 
He still made the decision on his own. Unless you forced him to.