A lack of filter means saying whatever is on your mind without considering politeness, appropriateness, relevance, or respect for the situation. People who have no filter may use profanity when they should not or bring up sensitive topics such as religion, politics, sex, body parts, or body odors in ways that offend others. Human communication follows social norms, and these norms discourage creating unnecessary controversy, embarrassing people, or discussing highly divisive topics in casual conversation. When someone ignores these norms, they may be seen as awkward, weird, or socially unaware, and others may feel unsafe or uncomfortable interacting with them. Appropriateness is a skill that can be learned by thinking before speaking, considering the audience and situation, and asking whether something is respectful, relevant, and suitable to say.
So long as it stays on topic, I don’t much give a fuck about politeness or how blunt you want to be with your message.
Also not talking about religion, politics, sex and related items is precisely what makes a human ignorant and disrespectful, not many things are worse than willful ignorance and the consequences thereof.
I’m utterly uninterested in those topics with 99% of people, because most of us (all of us) are ideological most of the time.
It’s the rare person who takes a genuinely curious perspective on these subjects.