The decision-making process is quite confusing.  That one council member would have voted in support of the grant if given all the information should lead us to question Costa's motives. 

"...At least one council member said the additional information provided Wednesday by the county’s energy and sustainability manager, Ben Sullivan, who was unable to attend their meeting last week, would have changed their vote.

“Had we had this information last week, this would have passed,” Rapozo said..."

Fear that economic development would point fingers at current practices (best or not)?  As much of Kauai's coastline is remote & inaccessible, maybe folk don't see a major issue.  But for the shoreline & coastal access that does exist, why not conduct a study?  Its business decisions, after all.  If tourist dollars are a major driver (they are), then making sure that rental & hotel properties remain intact is critical. 

Don't forget trump wanted a seawall to protect his Ireland golf course!