Thanks, that's interesting. One point I'm trying to work through is the importance of salience/ability to imagine others - i.e. is your 'autistic-traits friend' simply not able to hold a salient picture of people/animals outside of their social circle.
So while their gap between 'any given person' and 'person I actually know' is minimal; they simply are not able to imagine 'an abstract person' so their love of people outside their social circle is zero. Similarly, if someone in their social circle moves away or something, that person is no longer salient and is effectively excluded from all considerations of love (until the friend is prompted to think of them).
Conversely: since you are thinking about effective altruism, the potential recipients are salient to you rather than 'out-of-sight, out-of-mind'.
To fit it into the 'factors' I consider above, 'shared-experiences' are all forgotten and set to zero.
Thanks for the input, a lot of this writing is figuring out what love is to me. Where I ended up was that to care for someone or something else's welfare is to love them/it and then using love as a basis for allocating resources at my disposal (I ended up going down a rabbit hole on this one).
I found this to be a more comprehensive model and truer to my experience of love than the way I've seen it commonly referred to in media where it is almost a mind trap of 'obsessive thoughts' about another (much like lust but not necessarily tied to sex).