How does my "system of obligations to the rest of humanity" work?

I don't have a "system." This is something you made up in your mind. As far as obligations to the rest of humanity, I believe in the sanctity of life and good manners. It's not so hard to comprehend.
Right. But those 3 points of yours were a bit more than good manners. I wouldn't count contributing more to humanity among good manners by any accepted definitions, for example. We don't count someone's playing WoW for a total of 1 years of one's life and counting, instead of doing overtime, as bad manners.
At any rate, you must believe someone has such an obligation to contribute something, if that's an argument you use. You can't pass harsh judgment on someone for doing something they weren't under any obligation to.
Now you're drifting off topic. I don't have a "system," and we're talking about suicide.
So it was just special pleading after all?
There are lots of duties to society that override free will.
Right. So, since you're the one who started the argument based on the existence of those obligations. I don't think I'm unreasonable if when your argument is a case of "X => Y" I'm asking first to know at least what X is. You can't handwave in a conclusion without even defining the premise.
You're right... caring about yourself and others is not logical when it comes down to it. Self-preservation and the preservation of our species makes perfect sense though. Suicides make up a small percentage of our species' death, which is why I called suicide abnormal. Suicidal feelings and depression are obviously way more prevalent than the actual act. Feelings and depression are not "logical."
Homosexuality is also a minority and technically "abnormal". I don't think that makes it necessarily something to forbid.
I believe the dead people had an obligation to themselves and the people that cared about them. How far it extends is obviously debateable.
But that is actually the crux of the problem. Before judging if one falls on this side or the other side of the line, you must at least first define where that line is. At least approximately.
If someone doesn't live up to YOUR expectations (say you have a bad experience with an incompetent employee somewhere), you WILL pass judgement on them. You might say they're lazy, rude, or whatever. By doing this, you are not somehow transformed into the worldwide representative of all people who think that person incompetent. You simply had an expectation that wasn't met and you didn't like it.
Nevertheless, in doing so, I was essentially giving them an obligation that (in my judgment) they failed to fulfill. I thought they had an obligation to know this or that to do their job.
It's also a pretty easy one to explain. You can even put in numbers exactly how much you expect an employee to know, or to produce in a day, or exactly what kind of politeness rules you had in mind.
And even if one isn't inclined to compile some formal minimum knowledge requirements for a competent employee, it shouldn't be too hard to at least answer some questions about where some hypothetical cases fall. Should a Java programmer know that variables declared in the constructor aren't visible in another method? (True story: someone called me to ask why it doesn't work.) Yes they should, and I'll call someone grossly incompetent if they don't. Scope is a basic concept. Should they know how to write a JCA implementation? Nah, it's not something you do every day, and they can google it if they need to.
It _is_ a system of expectations and obligations.
Well, I don't like people who give up. With all the programs in place and treatment available, there are ways out. Suicide doesn't have to be an option, no matter how much you'd like it to stay on the table.
But actually giving up is a valid option, and often enough the smart option, in almost everything else.
One of the first things I learned in Go is never to throw away good pieces trying to save pieces which can't be saved. "I'm not giving up on that group" is the worst possible mentality to have. An even moderately competent player will wipe the floor with someone who doesn't know when to give up.
And the same applies to everything else. Those guys who end up paying 450,000 to some scam artist or 419 scammer, did just that: didn't believe in giving up. They already threw away some money, so they'll keep throwing good money after bad, because they're not giving up. They'll forge ahead and get their big payment. Yeah, right.
In reality the rational choice is to compare the losses and payoffs and likelihood thereof in all the available options. Including giving up.
Some people disagree with that sentiment. Knowing that does not piss me off or hurt me, though. I just can't understand why some people here seem to be saying suicide should be an option worth considering simply because we can.
I can't see why any particular option or situation would be above even considering.