The most important part is when someone bought it, that makes a huge difference in making a decision what to do next! Along with fiat/bitcoin holdings, there are too many factors, and we can't put all the people in the same basket! I am for more casual approach, always have some bitcoin on holding, when you can add more, always have some bitcoins for fun, gambling or trading! After all you need to have some fiat, if price make a surprise bearish move you need to have some money to buy that dip!
That is why the topic is continue to hold and not continue to buy. If it drops you buy at the bottom, if it goes high you sell at the peak and if it is right here you either hold or you do not buy. If you are not sure what to do just wait around, eventually bitcoin will bottom out again, it may not be 4k this time, it could be just 7k but you could still find a bottom and when you find a bottom you will be able to buy once again, until that moment you should not buy or you should not do anything that you might regret later on.
However if you own bitcoin it is still not a good time to buy more, but you could at least sell when it goes up, you are in big advantage over people who didn't buy from the bottom and now you can just wait and profit very soon when the price rises to a new level.