It usually surprise me when I see investors complaining about a good project that didn't increase or providing returns immediately it got listed on the exchange and they term it scam or say different things like rekted.
But the truth is, are these investors investing in the project because they believe in it or are they just in it for the immediate profit and move on? Because if you are investing in a project because you believe in it then you should be willing to HODL the tokens and wait for the team to gradually deliver the project and meet its necessary roadmap before you judge it and not condemn it on its first listing.
The opposite argument can be true as well. Rather than blaming the investors, I think you should first ask some questions to the ICO team and the promoters. Why do they always go for the listing even before the initial phase of development is complete? The most common excuse is that they need the funds for the development. But in my opinion, if someone wants to create the project, then he should be ready to invest his own savings, at least for the first phase of the development work. Most of the promoters don't want to do that and would like to transfer 100% of the burden to the investors. And the second question is why they always refrain from using the escrow to store their funds. If they use a trusted escrow, then it can give a lot of confidence to the investors, as they know that these guys are not going to run away after taking all the money.