You mean fake Christians?
Don't be a idiot. There's a thing called lying and faking. Your just referring to someone who wants Christians to look bad by acting or pretending to be one. It's common that there are fakes among any real ones.
Christians that do bad things I reckon are not Christians. You cant just say your christian and expect to be safe now. Like how you can't call yourself a cop when you just wear Halloween costume of a police uniform.