in all the alts except 1 or 2 like XLM and XRP which are performing well
altcoins get pumped all the time regardless of what is happening to bitcoin or the rest of the market. that doesn't mean they "performed well". a good performance means actually rising not having a pump that lasts 1 day then is followed by a dump!
case of XRP: from $0.47 pumped to $.51 then dumped to $0.43 that is not a "good performance".
or buy BCHABC (based on current volumes over exchanges).
if they were buying it then its price should have gone up not down. BCH has gone down from $430 ish to current $231 and the high volume speaks of the dumps that is going on!
Does it show that the technology underlying is not worth anything and people can become victim of any such bastards anytime and would sell off their money (Yes, BTC is your money) for lower?
it is because the price is determined on exchanges and these exchanges are pretty small still despite the high volumes the orderbooks are not as packed as you may hope. so a small manipulation can cause a big drop.