Unethical does come into play here.  

 One standard the city Ethics Board must uphold is for their members to not act in an inflammatory fashion.  

Guzman wrote this letter to the local newspaper, publically taking the council candidate's words out of context -- meaningfully intending to inflame.  

Her words are not the words of an ethcal, calm, cool, collected and professional city representative who is committed to upholding her obligations as per the Langley Municipal Code Ethics Code.

Preamble :   
Item A.  "We are obligated to make decisions and implement policies free of coercive or other improper influences."  

And, item F.  "We do not treat any citizen preferentially. To perpetuate public trust we avoid even the appearance of impropriety."

This letter was meant to influence the public, and cause damage to this candidate.  It apparently was written heatedly.