So people complimenting are actually prejudiced against? That's quite a stretch. It's impressive, if nothing else, the span of computer history he's witnessed and continuously was a part of. 63 was practically since the beginning. Also, most people at 74 either don't want to work anymore or (more likely) aren't able to due to their health. So it's doubly inspirational that he/she has the same enthusiasm at 74 that they had at 20.