are not good qualities of a prince.  He should be out helping his people.  Instead, he thinks that he can escape death and can party with all of his friends.  He does not want any talk of the disease, and he wants everything that goes into his party to be fun, extreme, and inviting.  He wants nothing to do with the ugliness of the Red Death, which is why it comes after him.

Prince Prospero shuts himself away in his fortresslike abbey to escape the terrible plague that is raging outside. During the fourteenth century, when the story is set, a horrible disease called the Black Death spread like wildfire across Europe. The bubonic plague, as it is also called, killed about 60% of Europe's population. Medical knowledge was pretty basic in those days, so no one had any idea of how the plague had started or what could be done to stop it. As a consequence, about 25 million people died a horrible, lingering death.

The Black Death, like the Red Death that stalks Prospero's princedom, did not respect class status or wealth and counted numerous members of Europe's leading aristocratic families among its victims. Prince Prospero is determined not to be one of them. If anything, the Red Death is even more deadly than its black counterpart. Around half of Prospero's subjects have died as a result of the plague, and he is desperate not to join them. He thinks that by locking himself and his upper-class guests behind the castellated abbey walls he will be safe from the ravages of the Red Death. He also thinks that the Red Death is a great opportunity for everyone to have fun and enjoy themselves; it will take their minds off the misery, death, and suffering outside the abbey walls.

We can find an answer to this question in Paragraphs 1 and 2 of the story.

Prince Prospero and his followers retreat to the palace in order to hide from the "red death," the highly contagious and lethal illness that's run rampant through the rest of the country.

The prince only brings his healthy, happy friends with him, a great many of them, and they lock themselves into his "castellated abbey" to keep themselves safe from the infected citizens outside, and to amuse themselves with entertainment, food, and wine.

Although they act as if they aren't afraid, they know that outside the walls of this building is a terrible disease that causes copious bleeding, one that will kill you within thirty minutes once it's infected you.

If you're wondering why Prince Prospero is hiding and partying instead of using his vast wealth to help the suffering citizens of his country,  you'll be satisfied to read the rest of the story and see what happens to them inside that supposedly "safe" palace!

In "The Masque of the Red Death," by Edgar Allan Poe, Prince Prospero is established as extremely disconnected, both physically and mentally, from the world around him. As the plague destroys the population around his castle, he remains "happy and dauntless," bringing in a thousand of his closest friends in order to weather the storm of death in mirth and merriment together. He seals off his castle from the outside world, stocking it with ample provisions, and believing it "folly to grieve or to think," as "[t]he external world would take care of itself."

Prospero believes his wealth separates him from the problems of the larger world around him, as this act of seclusion attempts to prove. The prince and his guests remain separated from the world, during which time they do nothing but engage in mirth and pleasure. As a means of celebrating their believed invulnerability, he throws a magnificent ball "toward the close of the fifth or sixth month of his seclusion, and while the pestilence raged most furiously abroad." It is at this time that the prince and his fellow revelers experience the harsh reality that nobody is safe from the plague. As the clock strikes midnight on the night of the masquerade ball, the Red Death makes its presence known, sweeping through the crowd of revelers and killing all of them, including the prince himself.