Do Jews Believe in Hell or Not? Or are They Confused?

I have heard both sides. Some Jews say there is "Gehinom." Others point out that Tanakh does not mention it. Talmud believes in Hell. For example it says, "Erubin 21b. Whosoever disobeys the rabbis deserves death and will be punished by being boiled in hot excrement in hell." So why do so many Jews deny the existence of Hell?