Utopia is chock full of social commentary. And when Hythloday gets to Utopia, he's pretty taken with their unorthodox way of eliminating wealth: no private property. Without private ownership, there is no such thing as wealth—or poverty, for that matter—and people just don't care about being rich. This works out well, says Hythloday, because then there's no greed; and when there's no greed, everyone is happy. Everyone except him, of course, because it reminds him of how money-driven European society really is.
Like it or not, ownership of things makes us happy; it's completely unrealistic that people could be happy in Utopia.
If Hythloday hates wealth so much, he shouldn't be hanging around with his wealthy friends all the time enjoying their food and beautiful gardens.