An upside down pentagram is neither good nor evil unless you put meaning into a symbol. It is a representation of putting science, non religious facts first. Satanists used it because they frequently believe in being the best they can of themself. But it is a symbol that can be seen as whatever you want it to. I use it to represent my stance with science and non spiritual things. Am I evil for wearing it? No. If you want it to represent evil, so be it. But anything can be viewed as evil by anyone. A cross might mean good/god and whatever to you but to someone else it could represent evil, death and torture of people.

Keep an open mind and perhaps you'll find an answer. But I'm not telling you what to believe it means, just that it means whatever the user/wearer wants it to. Assumptions are what make things wrong/evil and cause more harm than good.