Pump dump dumb

I’m trying to understand pump and dumps better because I hear the term thrown around constantly in crypto. Is a pump and dump basically just coordinated price manipulation, where a group buys in, creates hype, pushes the price up, and then sells into everyone chasing the move? Or is there sometimes a money laundering angle involved too?
Also, what actually makes a token especially easy to pump and dump? Is it usually a low market cap, low liquidity, thin order books, or a small number of wallets controlling a huge percentage of the supply? Does being listed on smaller exchanges make it easier too?
I’m not asking how to do one. I’m just trying to understand why some coins get labeled “pump and dump coins” while others don’t. What are the biggest red flags to look for if you’re trying to avoid getting caught buying near the top after insiders or early holders have already pumped the price?
Is there any way to tell a legitimate rally from a coordinated pump before the dump happens?