Right now people who bought bitcoin when it had a higher price are only suffering from a *potential* loss. If you chose to sell at this price, then you transform that potential into something concrete and you will incur an *actual* loss.
As Jet Cash said earlier, this is actually good for the ecosystem, because all those speculators who saw bitcoin as a get rich quick scheme are weed out and only those who are actually interested in developing the ecosystem will remain.
And maybe this price drop is for the good, settling the price around $4000, and then sit there for a long time, transforming bitcoin in a store of value, not just a means of payment. And if you look at the fundamentals, with limited supply and market penetration of only 10% (according to some optimistic opinions), there is a strong foundation for secular growth in price.