I once hold a coin and suddenly the coin that is almost $1 dump to less than $0.01 to me I move on but to some people which are newbies this can discourage them from participating in crytocurrency and make them conclude it is fraud and that brought me to a question how do you think pump and dump group are damaging crypto-currency and it's reputation??
Because they are controlling and manipulating the market. They can do whatever they want with the market because they have a lot of funds to manipulated the market.
Some people arguing about that they are luring newcomers to FOMO the coin and they bought at high price and then the pump group was dumping it again.