Depending on your By Laws,if it's majority rules,you've passed the motion to spend the $6MM.
In practical terms,there's probably a good chance that some of those opposed plus some of the non-voters will resign.Presumably,this was factored into the financial projections and wasn't a deal breaker to the club's Board.
For a club to even think about $6MM in capital improvements/assessments in today's environment strikes me as unusual.To go through with it must mean either a very well-off membership or a suicidal Board.