The manipulation are really scary especially if you have high position and then suddenly a huge dump appear, most of the new projects have manipulators where the volatility really spike hard. Imagine you buy then suddenly huge dump appeared, how can you able to handle it? it is the reason why I often avoid buying new token that is recently listed because most of it are just dumping so for me it is better to avoid than to incur huge amount of losses.
Manipulative action is absolutely not justified because it will only benefit a few parties. I don't think it will happen to top coins, maybe it's just some "new projects" that have such an action. so before investing in a new project make sure you do thorough research as a preventative measure.