I’m not saying it is objective, I’m saying it’s not arbitrary.
If my dna was isolated in a test tube and it could experience things then I would also care about what it experiences. There isn’t any evidence I’m aware of that that’s the case. Dna is the instructions and tool to build the sentient being, not the sentient being itself. So no, the same couldn’t be said of dna. Extrapolating from how much I care about what I experience, I think it’s reasonable to care about what things that experience things experience