There are many reasons why members are resistant to this kind of change; the main reason is simply that people are resistant to change! I'll give you a specific example. When I was on the board at Olympia Fields, we voted to change our 18th hole on the North Course from a par 5 to a par 4. As it has been played for several decades, the hole, which is 495 yards from the back tees, with a pond that extends in front of the green about 65 yards away, has played as a par 4 from the blue/black tees and a par 5 from the white tees. This led to the incongruous appearance of the white tees being behind the blue/black tees. In any event, the average length of a par 4 at the North Course is about 430 yards. Our other two par 5 holes measured around 580 from the back tees, so we felt that a short par 4 was a cheesy way to end a man-sized golf course, so we voted to play it as a 440 yard par 4, which was more fitting to the nature of the golf course.
Three days later, some member floated a petition to undo the change and 150 members signed it and we reversed the decision. Ultimately, it is true that par doesn't matter and one just plays the hole, but psychologically it seems lame to me to have a hole where the usual play is driver, seven iron, wedge and two putt for a par on a course where a 440 yard par 4 is de rigeur...