Sounds like that person doesn't really understand that NASA is a political entity and the Public Relations of an ongoing successful mission is more valuable long term than more scientifically pragmatic experiments in the immediate.
People have to be continually convinced that exploration of the solar system is a worthwhile expenditure of a lot of money that could be spent on other things. Seems obvious to those who are already thinking in the direction of where humanity is going, but most people do not.
Not to mention, science without proper PR has a disastrous level of near-term utility. See: climate science