There's a major difference - actually two - major differences.
The first is simple - Sam agrees with you here, and back on the procreation thread, he didn't. Therefore, he'll accept whatever argument you present as evidence here, even though he argued with it back there.
Second, when we're talking about one of us specifically (or me specifically, since I brought it up) contemplating suicide, we're talking about an act of free will on my part. I believe that to live is to suffer. I've even begun using the words interchangeably on occasion. I believe it was immoral for my parents to procreate when they spawned me, but now the choice of whether to kill myself to escape the suffering that is life or continue living is my decision. Maybe the level of my suffering isn't severe enough for me to actually go jump off a bridge and kill myself. Or maybe I just don't have the balls for it. Or maybe there's some part of my soul that still believes in miracles and fairy tale endings and is holding out hope to see a vegan utopia become a reality within my lifetime. Or maybe I'm just being selfish and I want to enjoy my new 54" plasma TV. The point is that the choice is mine and mine alone, AT THIS JUNCTURE IN TIME at least. Back in the 1970s when my parents were contemplating whether or not to have any kids, the choice was not mine. And so I'm choosing to stay alive, and with that, I have the potential to influence people in the future and hopefully steer them in the direction of veganism.
But where you err is in that you mistakenly use the potential good that can result from creating and influencing vegan children (who can then in turn influence others in the future) as a justification or rationalization for procreating. THAT is what's consequentialist, because it neglects to recognize the middle-man. In other words, it doesn't recognize that the mere act of bringing a new life into the world, one which you KNOW is going to suffer simply for having been born, is itself an immoral act. You can try to moralize it by saying the overall greater good can be accomplished by procreating, but that's utilitarian and fails the moral parsimony quiz (at least if you agree that to live is to suffer).
It's not just that being alive puts one in the inevitable position to endure inevitable suffering. The fact of the matter is with world governments operating in their current manner, we are all slaves and we are all being exploited without exception. Why anyone would want to subject their own children to this kind of existence (in addition to the natural suffering that is part of life in general and has nothing to do with government, politics, or authority) is beyond me.
Getting a little back on topic, or at least tying this together a little, I think the thread starter was hinting at the common criticism of veganism that speciesists see as a slippery slope, i.e., today we're trying to protect animals, next we'll be trying to protect insects, then plants, and eventually we'll prioritize every life form above humanity, and we'll have no choice but to extinct our own species. On a practical level, like I said in another post, I'm an immoral being because I'm indifferent to the potential suffering of plants - at least the ones I eat. But on a more theoretical, philosophical level, I make no attempt to hide my disdain for humanity, and ultimately, that slippery slope (that the scares the ever living shit out of speciesists) leading to the extinction of man is a goal I see as noble and ideal. Those who disagree with me are simply insecure and have a desperate need to protect their "legacy." They think they can become immortal by procreating and having their genetic code preserved after their deaths. One of the most selfish acts possible is to create a human child, not only because that child will suffer, but also because it delays the possible extinction of the human race.