I don't think that is the reason for the pump in altcoins. Especially in xrp, there is this even in xrp which is the spark token airdrop. We can see this as a reason for the increase in the price of xrp, it does not harm the price of bitcoin or even manipulated by the pumps of it.
I see whales are the main reason to play along with this coin. It could also be the owner of the coin in which he could pump up or pump down the coins due to his huge holdings. It might be not good if you as a trader will not be able to get along with during the pump and dump. However, if you know and smart enough with the situation of some altcoins like XRP then you can earn in it even greater than investing in bitcoin. Just always remember the best time when to invest your money in these altcoins.