Define bad and define wicked.

Popes were important political players in early modern Italy. What one man or political faction could consider wicked someone else could consider pragmatic. Popes were similarly characterized differently depending on who was talking about them.

All told, Popes were men in power. The mob usually resents of men in power. Calling someone wicked or bad is an easy way to pander for popular support.

Is there any specific Pope, time period, or aspect of papal politics you're interested in?

To my knowledge, there was public "knowledge" of assorted popes misdeeds - sometimes accurately, sometimes not. During other times, popes were widely known to have taken a mistress - Alexander VI had three children with his old mistress. His daughter he married off to a wealthy son of a family he wanted to ally with. His one son became a cardinal and the other was military-focused. He also had another mistress while pope. Aside from that, keep in mind that popes were/are basically politicians and therefore are not exempt from attack-campaigns and smear campaigns. Sometimes popes did what they are said to have done. Sometimes detractors started rumours to create dissent. For example, one pope is said to have ran a brothel out of the vatican. Even for the corruption of those days this doesn't exactly sound realistic so we have to take it with a grain of salt.