One joke, told in Czech, involved rhetoric. I couldn't quite follow it, but everyone who speaks fluent Czech laughed. I imagine that they were making fun of the use of rhetoric by politicians. Czechs love to insult their politicians, who make (as many Czechs believe) empty promises and grand, meaningless statements.
This is, of course, one use of rhetoric, the art of persuasion. Politics, business, education, and religion all are guilty of misusing the power of rhetoric towards their own ends. Good rhetoricians can "carry people away" with their ideas and offerings, causing normally cautious people to agree to things that they later regret.
But is it fair to blame the art of persuasion, invented and perfected by the Greeks, for the people who misuse it? No, it's not fair at all. The power of rhetoric is the power of well-arranged, meaningful words. Mastering rhetoric is a life-long pursuit, worthy of respect.
Would you make fun of triathalon winners because some poor out-of-shape guy couldn't finish the competition? Would you call French cuisine a fake because one shabby restaurant, with an untrained chef, produced poor French food?
Of course not. Rhetoric is a tool; how people use that tool doesn't determine the value of the tool. Rhetoric is art; the level of talent of the artist doesn't determine the value of all art. The more you know about rhetoric, the better you can identify the charlatans of rhetoric. They won't be able to fool you!