In the case of meat, the argument is that humans aren't human enough to justify protecting them against killing the way humans protect other humans.
That’s not an argument for killing animals, so presumably you mean ‘the animals aren’t human enough to justify protecting them against killing’?
An animal is sentient and capable of feeling pain. A woman who's life is destroyed by carrying a foetus she does not want and did not chose more so.
Down syndrome/severe autism like genetics aside (because I’m not including such in the following question) do you have examples of “A woman who's life is destroyed by carrying a foetus she does not want and did not chose more so.”
You need to investigate the meaning of "rights". A fetus does not have any.
‘Rights’ are a form of group consensus, (and rights are formed out of) a agreed upon 'principle' arising out of issues of morality, ethics, fairness etc. As such, the concept of ‘rights’ are created subsequent to the concept of morality, ethics, fairness etc. As example:
- in times past women bathing in the sea had to wear excessive coverage, and did not have the right to wear a bikini (similar things happen today in some non western countries). These things were not a right back then, but are now.
- In some countries there is religious freedom, in some there has not been. In the ones that didn’t have it, it was not a ‘right’, but most in the west consider this a right
- In some countries there is the right to vote, in some there isn’t, so it is not a ‘right’. In the ones that didn’t have it, it was not a ‘right’, but most in the west consider this a right.
- In some countries, freedom of speech is a right, but other countries repress it. In the ones that didn’t have it, it was not a ‘right’, but most in the west consider this a right
- it used to be a right to own slaves, and slaves did not have many rights. Yet now the descendants of those same groups embrace 'freedom' as a right.
So are the above rights or not? The answer is they became rights when agreed upon by the masses, or those in power. So a ‘fetus does not have any rights’ is subsequent to the morality, ethics, etc that gave rise to the line of thought (ie. the 'right').
Livinglava’s original question is the about morality behind that right, not the subsequent right itself.