I understood it to be a self-centered statement (meant to explain, not judge). “Meaning” is something that exists in your head. You care about the state of the world because your cares are a state of your mind. Kill the mind, and there’s nothing left to do the caring.

The first objection is often “but I care about other people whom I will leave behind!” But yes, you care. Once you’re gone… there won’t be anyone left doing that caring.