Edison was often portrayed as Tesla's rival in early literature about Tesla, which is not quite true. There is no evidence that Edison "stole" ideas from Tesla in the sense of breaking the law. Rather, Tesla worked for an Edison company at one point and came up with many ideas which Edison profited from. Tesla's comparative lack of interest in business and profitability made this arrangement seem unfair to some biographers, and Tesla himself felt that Edison ran his business in a way that put profits before people. See my answer here for details: Did Edison refuse to pay Tesla, saying “You don't understand our American humor”?
When Tesla became independent and competed with Edison with the help of more businesslike partners, Edison used many marketing techniques to try to win the battle, including some we would regard as inhumane. Details here: Did Edison publicly electrocute people's pets to present AC current as dangerous?
There is no evidence for Edison "stealing" or maliciously being a dick to Tesla. The relationship between them was not one of abuser and victim. Rather, Edison desired to capitalize on his company's electric innovations sometimes even to the detriment of public safety or scientific merit, while Tesla was more interested in seeing innovations adopted based wholly on their merit and regardless of economic benefit. It would be fair to say that Edison and Tesla had different enough value systems that statements like "Edison was a dick" can be produced from the comparison, based on the speaker's own opinions.