This always happens when the price is in a downtrend...The ones stuck in fiat who missed the rally from $100 are trying to get others to panic and sell so they can buy bitcoins for cheap...
Some of them are trolls and just want the attention...best to ignore them...
Yes, this was common strategy of some users to decrease the price of bitcoin so that they can buy it in a cheap price. Other reason also id they didnt know what they are doing in the result they think that bitcoin is dead.