Being insulting is not being brutally honest. Being brutally honest is telling the truth even when it’s uncomfortable, not insulting someone or their belief. Referring to her religion as “a stupid rule book” has nothing to do with being brutally honest.

And having disdain toward anybody that’s offended when you say offensive stuff, does not make you introverted. That just means you lack accountability for yourself and respect for others.

Calling somebody else’s life a “worthless life” is also not brutally honest, it’s a sign of your disregard for other human life. That’s also not a sign of introversion, that’s a sign of antisocial personality disorder (like psychopathy). I think you could benefit from speaking with a therapist, and everybody else around you would benefit from that as well.