Correct.
For the entire purpose of sex, and everything around it, is reproduction, brought to you by your friends at Natural Selection, Inc
Nope, "purpose" is a human construct. People don't "have to survive" unless they want to.
And in the modern world, threats to survival are rare. Our population is far larger than what we need to merely "survive" as a species, life expectancy is longer, and infant mortality is rare. This is why people have fewer children in the modern world than they do in the undeveloped world.
We could cull our global population down to just 150 people and still "survive" as a species, so having billions of people on the planet does not in any way aid our "survival".
Its not some evolutionary holdover or quirk or vestige or some other non-essential --
It is. It's an instinct which developed from the reptile brain.
The reptile brain engages in many behaviors which would have aided our survival in our primitive past, but don't aid us in contemporary life, such as the "fight or flight" response.
it is literally what nature gave the species as a means to guarantee its survival.
Right, and as I said above, survival doesn't matter.
Our more-recently developed neocortex allows us to rationalize that "survival" may not actually be all that important, and that focusing on things which improve quality of life (e.x. sex for pleasure) rather than those which merely sustain life are a better option.
To simply dismiss all that it to hate the science.
Ultimately, science is bullshit. It's simply a dated amalgam of information gathered by humans which originated centuries ago, and we could easily devise superior systems of gathering information. To have any utility, science requires interpretation.
And you're grossly misinterpreting it.
That's not what you said, son.
Its all on record, Go back and re-read.
What I said is that it doesn't matter if a zygote is biologically alive or not. Skin cells are biologically alive. They contain human DNA.
But when we talk about an individual being a "human life", we're referring to their consciousness, not to their body being a "biological organism".
So, since a zygote has no brain or consciousness, killing it doesn't matter.