I do not not understand how the value of a human life is subjective. Other animals do not love the way we do, are not self-aware the way we are, and are unable to advance the way we can. If we lose our value of life than we are no more than animals. I used to somewhat feel the way you do but over time I gained empathy and compassion and it has greatly enriched my life. I'm not Mother Theresa, I just honestly care about others.
I didn't posit how I felt. I retorted with a question. Subjectivity vs objectivity is the difference between a thought relative to some number of people, versus an absolute value. An absolute would be something to the effect of "all things in their composition contain atoms." We presume this to be true, beyond a reasonable doubt, because that is our scientific understanding of matter.
Saying, "life has value", is subjective because we can't know with specificity what value it has in absolute terms. You presented the statement on faith that value of life is universal, but we know that not to be true. Most of the value statements are circular because they have no provable objective statement of value. Statements of "live has value" may also take on faith that it has value because it is said that it does. Saying, for instance, my life has value because other need me fails the test because others do not apparently posses an absolute value either (in other words their existence is just as transient, and no obvious purpose is apparent). Similarly, value relative to some understanding of a god-thing is not provable. Life may in fact be meaningless and have no value, it maybe the most valuable thing, or it may only be as valuable as a person believes it to be to themselves.
It is a ponderous topic, the meaning and, or, the value of life. It is not provable that life has absolute value. If it means something to you, it is proper to say that it has some value to you, but that it may have lesser, or no, value to someone else. I don't begrudge anyone their feelings, one way or another. The OP's feeling, and those a like, are valid simply on the fact they are feeling them. Whether they are trivializing something valuable, I don't know the answer too that. It's an interesting topic though.
So, what makes life important?