Evolution is also a human construct. It doesn’t do, or think.

That last also seems to define the purpose behind religion, too.

Anyway, natural languages are inherently ambiguous. “Absolute” and “objective” can and are frequently used synonymously in common usage. You’re right that “moral objectivism” and “moral absolutism” have very distinct definitions in philosophy; I doubt that people without a deep interest in philosophy are typically aware of this (I wasn’t until I took the time to look these things up).

This is less a matter of sloppy language and poor word choice than it is one of unfamiliarity with precise philosophical definitions.

You are correct that objective morality means that morality is independent of judgments made by people (i.e. there is a right thing to do in any given situation and it is our job to find out what that “right” thing is).

Equating “absolute” and “objective” however, is sloppy use of language. It might suffice in other spheres, but in philosophy, absolute morality is involved with universal principles that don’t take situational factors into account (NEVER lie, kill cheat, etc.) while objective morality simply requires that “good” and “bad” exist as real values in the moral sphere.

That’s a huge difference–moral absolutism is absurd and nearly impossible to justify, while moral objectivism is accepted (with variances in form and degree) by the majority of contemporary philosophers.

Be careful with your words. For starters, check out section 1.6 here:
http://home.sprynet.com/~owl1/objectiv.htm

Also, cannibalism doesn’t seem to be any kind of bad thing, even to christians. Most people would be grossed out by it, but as long as you’re not killing people so you can eat them I would assume it’s perfectly OK.

I’ve never met a person who thought he could be like god. I only meet people who tread upon the territory other humans say their god only has access to.

“No, no, don’t site there, that’s god spot.”

“But there’s nobody here?”

“I know, it only looks like god is not there, but he is. Don’t sit there, sinner.”

Someone who believes in objective morality believes that morality is independent of any judgments made by people. “Objective morality” is more-or-less synonymous with “absolute morality.”

In other words, moral objectivity is not equivalent to moral Objectivism.

I wonder if people who believe in objective morality would find cannibalism immoral if it was the only way to sustain a population, if it was essential to the survival of human life?

You’re still a little confused on your terms. I think you meant “people who believe in absolute morality” not objective morality. A moral objectivist would simply hold that whatever is right for one person in that situation is right for anyone else in that situation (whether it’s deemed right or wrong probably depends on more specific circumstances and a much better understanding of nutrition than I can offer).

I think you meant to ask about a moral absolutist–whom you seem to assume would believe that cannibalism is absolutely wrong under any circumstance.

Do you see the difference? It’s important.