As I get older, I read this entirely differently (as an appeal to empathy) than I did when I was younger (as an appeal to stolidity).
In other words, you should be pained for your neighbor when his slave breaks his cup. Maybe his grandmother left him that cup, and he's developed many fond memories around which he drank a soothing beverage in that heirloom. That empathy how we connect with people, build meaning, and make life richer.
My initial reaction was to disagree, but the man did allegedly take in an abandoned infant. And a woman to care for it[1]. And, our readings[2] of that quote (acceptance vs altruism) aren't in any way incompatible.
[1] You absolutely don't want to be a single woman in 1st century AD.
[2] acceptance vs altruism
From just the quote above, I understand more as something intermediate : don't be pained when your cup is broken, like if it it was the cup of some else but be pained when someone else wife or child die, like if it was your
• Pop stoicism is an anesthetic for the powerless.
• Classical stoicism was an anesthetic for the powerful.
• Both suppress the self in service of an external system.
• Neither are about empathy.
What treatment of the slave does the broken cup’s provenance justify?
That's probably not how the stoics meant it though.