POTENTIAL SPOILERS?
I mean, what I take is that he potentially won't live as much as the rest of the crew. And that's the sort of thing that pisses me off (quite a lot). In a sci-fi scenario where everyone can live centuries, if not more, the MC being restricted to the default for no good reason (aside "character building") leaves a sour taste, at the very least.
And makes pursuing any love interest, well, completely irrelevant. Since the MC isn't supposed to live as long as them. Why bother on the first place?
It's a bit of a prickly subject, for me in particular, or perhaps my brain is too nitpicky on some details that are actually not very relevant. Again, if this detail is related to the plot in more depth, I won't pry further to avoid spoilers.