That's exactly how I see it. They view any suicide as an attack on their own values, and their belief that life is worth living at all costs.
The philosopher Schopenhauer had a great bit about this. Although, he was speaking more about religions with regard to suicide than pro-lifers in general; it still hits the nail on the head:
If we abandon that high standpoint, there is no tenable reason left, on the score of morality, for condemning suicide. The extraordinary energy and zeal with which the clergy of monotheistic religions attack suicide is not supported either by any passages in the Bible or by any considerations of weight; so that it looks as though they must have some secret reason for their contention. May it not be this—that the voluntary surrender of life is a bad compliment for him who said that all things were very good? If this is so, it offers another instance of the crass optimism of these religions—denouncing suicide to escape being denounced by it.
The most relevant portions being
"
May it not be this—that the voluntary surrender of life is a bad compliment for him who said that all things were very good?"
"denouncing suicide to escape being denounced by it."
This is both a good and bad thing, for me personally at least. I appreciate that my suicide will be a massive middle-finger to these preventionist assholes, especially given the fact that I'll have used a method that they so desperately want to restrict. But the fact that they view suicides as an affront to what they hold dear also means that making progress toward a Right to Die for All is all but an impossibility. I don't know if things will ever change. Some people equate the RTD issue with slavery in that, racism and slavery used to be the majority and popular position, and then things changed over time as conflict ensued and social progress moved forward (in the western world, that is)
. But given that the RTD is directly anti-life, I don't think one can equally compare the two social issues. People are both culturally programmed and naturally inclined to favor life. And governments won't like having their worker bees just check out of the hive whenever times get tough (even though there's the argument that they might prefer to euthanize citizens over covering their social welfare needs). So who the hell knows if the RTD will ever be meaningfully implemented. We can barely get it for terminally ill people, or those with incurable suffering. I think the next line to cross - allowing people with mental illness, is gonna be a huge hurdle (though some countries are making an effort to implement this). And I can't even imagine a society allowing anyone 18 and over to simply cash in their Right to Die token and check out.
I think they lack empathy because they can't see other people's side of things. They may have had suicidal thoughts themselves at one point, like you said. But since they got over it (perhaps their issues were trivial or transitory), they think everyone else will just get over it. Even if one has been wanting to CTB for 10-15 years, they'll tell you to keep on keepin' on, like things will just magically get better one day, or that it's even worth it to wait for things to get better. They also almost always think of things positively, as in - only thinking about how things will get better, as opposed to how things might get even worse. They only look at one side of the coin. Maybe this is due to their own personal experience, or the fact that optimism is so heavily ingrained in many cultures globally.
Another reason they may not be willing to allow suicide is because it'd cause them to consider suicide as a valid option. As Thomas Szasz said, society is filled to the brim with anti-suicide propaganda. Just about everywhere you turn, everyone you talk to, is against suicide to some degree. And because suicide is seen negatively, they do not want to consider it for themselves, nor want anyone else to consider it. So they not only want to take away other people's ability to make their own choices, but also take away the choice from themselves. For some, it almost seems like they get off on it.
Religion is also a huge factor, since Christianity, Catholicism, and Islam all say that life is a gift from God (or Allah). And taking your own life is an affront to God, and you'll go to hell for it. So with the religious, you'll never be able to win them over on the RTD issue. They get pissy whenever someone with terminal cancer gets euthanized. That tells you all you need to know.
My train of thought has taken a shit. But that's what I think about this.