>>Of course it is wrong to say there is a "scientific consensus" that sex is a spectrum>>

Correct

>>but equally wrong to say there's a scientific consensus it's binary.>>

Wrong, at least for humans and other mammals, and other animal species. The scientific consensus is very, very strong, because there's zero empirical evidence to show a third sex.

>>Scientists do not even think there is any objective answer to the question of which arrangements of particles are "life" (for example, is a virus life?), much less which ones qualify as "male" or "female", the definition is a matter of utility and nothing more.>>

"Life" is much, much more difficult to define than sex. The definition of "sex" is certainly, like anything in science, a matter of utility: does it work to explain what we observe, and does it work also to predict other things or events that we haven't yet observed? The binary definition of sex (around gametes) works really well on that. A "sex as spectrum" definition doesn't. We know that phenotypical presentation varies. That doesn't mean we need to redefine sex. You don't say that someone who gives birth must be male just because they're over 6ft tall. You'd say they're female because sex is predicated on what happens with gametes, not secondary characteristics. A definition that varies from one moment to the next is not the basis for a scientific framework.