Nick Tarleton said it well, but to try it another way: Depending on how you phrase things, both to yourself and others, the situation can appear to be as bleak as you describe it, or alternatively rather good indeed. If you were to phrase it as being stuck with a brain built for chasing deer across the savanna and caring about the few dozen members of your tribe, being able to try to gain money (because it's the most effective means to whatever your ends) and investing some appreciable fraction of it in the cause with highest expected future payoff, despite being abstract or far in the future, starts to sound fairly impressive -- especially given what most people spend their time and money on.

If Starbucks lattes (or more obviously living above the subsistence level) makes it more likely for me to maintain my strategy of earning money to try to protect the things I value, my indulgences are very plausibly worth keeping. Yes, if I had another psychology I could skip that and help much more, but I don't, so I likely can't. What I can do short-term is to see what seems to happen on the margin. Can I sustain donating 1% more? Can I get by without a fancy car? House? Phone? Conversely, does eating out regularly boost my motivations enough to be worth it? Aim for the best outcome, given the state of the board you're playing on.