No one's honor is at stake, of this there is no doubt - scratch this reason for going.
No, "honor" here IS the relevant reason. By your presence, you honor the deceased or the person(s) the ceremony is about.
Thus you can attend the funeral to honor a deceased relative, or deceased friend, or a deceased head of state (an example of honoring someone you may never have met).
Doing so is an act of virtue, but as a non-theological virtue it can be limited by potentially giving scandal or endangering one's faith.