“I’m just honest” doesn’t cover being mean. Honesty with no care is just aim.

Honesty and care are separate ingredients, and truth without the second is just a well-aimed hit. You can tell which you are doing by who the comment serves: help points at their situation, the other kind at how you will feel afterward. Being accurate is not a defense, since true things can be picked because they will hurt. Most people know which they are doing while they speak.

Before the next blunt thing, ask what you want them to be able to do with it. If there is no answer, honesty was not the point. Try saying the same fact to someone you love and see whether the phrasing survives.