What is "selfishness"?
Everyone is inherently selfish. Everyone's body and biology is different and they need to get what their body or self needs. Its simply a biological thing and not something to be shamed of. Even "non-selfish" or altruistic acts are essentially selfish. Whether being selfish or not doesn't matter and the context is whats important and shouldn't be used to shame or pressure others. So lets compare the two scenarios, a self thats suffering but feeding other people's "selfishness" by staying alive, its still selfish for both but the first is influenced by the selfishness of others that don't actually know their pain. In the second scenario, leaving the world and making them sad instead of living, its both selfish, they became sad because of seeing someone die but never understanding the suffering and therefore aren't actually sad because of the suffering itself and that person chose to cut suffering. Unfortunately, everyone just look at their point of view, not others point of view and thats one of the fundamental and inherent problems in life.
Selfish or selfishness are meaningless words that are used to push some choices and shame others while living as a human is completely based on self. What matters is the context and choices, not whether something is selfish or not.