Your reluctance is both common and understandable. But it's actually not that difficult to reconcile. Let's talk about this from an egoist perspective. First of all, why should you care about other people? Simple: other people are a potentially valuable resource. Despite protestations otherwise, many smart people labor under the delusion that they are of singular genius and importance, and thus have a very difficult time truly grasping the idea that other people can be as valuable as they themselves are.

Your car, computer, bike, house, appliances, etc. are all resources that can accomplish certain ends much more efficiently than you can. So it doesn't feel alien to put your own short term needs secondary to the long term maintenance of these resources. The reason it feels so alien to do the same thing with people is that you haven't quite internalized the value of other people.

But what does that have to do with valuing other people's success more than yours? Simple: if you've already made the right meta-cognitive choices, then the incremental value of spending "unallocated" time on yourself isn't all that high. If you already devote an hour a day to reading, then opting to spend two hours at home reading on a weekend instead of going out doesn't really provide much incremental benefit. If you are confident enough in your own life choices, then you don't need to spend much active time on your own success because it's already taking care of itself.

The stereotypical charismatic, socially adept extrovert tends to be much more confident and slightly less "intelligent" than your average LWer. Why is that? First of all, they're not worried that the time they spend on others will affect themselves negatively. And because they aren't as "intelligent", they have a more acute awareness of just how valuable other people can be.

TL;DR: it only requires a fundamental change in your values if part of your fundamental value system says "other people are worthless". And it only requires a delusion if you decide to take the straw-man interpretation of my post rather than the reasonable one.