Coin list sites will list almost everything because they least care about the scam and only care that everything is listed on their site so people do not need to visit any other site for coin/exchange tracking. Even such sites will not hesitate to list the scam projects if those projects paid them.
You may use these listing sites to get general information about the coins but if you want to invest in any coin and/or in any exchange better do the due diligence yourself. The money is ours and we need to take the responsibility of investing it in the trusted project.