Of course, things are a lot more nuanced than what I'm about to describe, but you can typically sort those who are completely anti- right to die into two broad categories.
The first category is composed of naive optimists. These people tend to have a firm conviction in the mental health profession, indulge in spirituality, and constantly professs that growth stems from hardship.
The individuals in this group may have suffered some roadblocks in their life. However, they tend to have supportive family, friends, peers, and mentors who hoisted them out of whatever rut they were in. Society did not give up on them during their low points. The fact that the struggle was not chronic is the key here.
Vast majority of therapists and psychologists fall into this camp. There's an old stereotype that people go into that profession to try and understand their own problems, and it still rings true.
I would say many therapists are motivated by their personal experiences with brief lapses of mental anguish. Typically they have a strong desire to help people, which is often fueled by losing a loved one/ acquaintance to suicide or seeing others struggle with depression, anxiety, and so on and so forth. Hence, they want to fix others issues.
The people with this mindset typically have pure intentions, and truly think they are doing the right thing when they try to push someone towards toxic posivity or tell them that their suicidality is delusion. To them, all barriers can be surmounted, improvements can always be made, so it is asinine to ever consider suicide as a possibility.
They are indoctrinated to believe that every problem has a solution, whilst reality begs to differ. I saw a post on a subreddit for therapists where one of them admitted that she is forced to counsel homeless clients, but that this has little benefit to them, because what they actually need is a roof over their head, not cognitive behavioral therapy. All of the commenters essentially told her to shrug this off, because she can't fix the housing crisis.
Most of these people are quite privledged. In most countries it takes a fair amount of wealth and stability to be able to progress through higher education.
A lot of these therapists and self help gurus have struggled, but they never got to a point where it compromised their standing in society. See the news article I posted before about a young woman who conquered drug addiction and took on massive amounts of debt to become a doctor, only to discover that she was ineligible for any jobs due to her past drug convictions. She ended up catching the bus.
Failure to admit futility is a fatal flaw. Sadly, those who fall into this first category that I have described refuse to admit defeat in any circumstance. Their hearts are in the right place, they truly want to help and believe in the notion that everyone can be saved, but it's unrealistic. They tend to have compassion up till a certain point, then it begins to wax and wane, and the victim blaming and accusations that "you don't want to try to get better" start being flung at the suicidal.
Now, for the second category of anti-right to die zealots. This is the tough love, sacrifice yourself for the good of the economy and civilization crowd. They tend to say things like, "That's just the way life is. It's unfair. Deal with it. No one likes enduring pain, but it's a part of life, so get over it. You have an obligation to society, you know? "
Individuals like this have a pull yourself up by the bootstraps mentality and a tough love approach. Unlike the other side who think that you simply need to keep searching endlessly for the perfect therapist or yoga technique, these charlatans will insist you haven't suffered enough, because hardship will allow you to appreciate life more, in their point of view. Relative privation fallacy is typically in full swing.
They view their fellow man through the lense of resources and economic instruments. As others have said, people with this mindset tend to see human beings as a commodity serving to keep the cogs of civilization turning. They value a conglomerate's economic productivity, continued existence, and wealth more than the wellbeing of it's citizens.
Often times they are anti-abortion as well, traditionalist/attracted to the ideal of familial piety, and perhaps even downright authoritarian when it comes to their stance that all life should be preserved at all costs. You live because you have a duty to, not because you actually desire existing. They simeltanously harp on that life isn't supposed to be an easy cakewalk, while telling you that you're disturbed for being suicidal.
Both of these camps are hell bent on preventing assisted dying from being sanctioned. They have different rationale, but their goal is the same, to force the continuation of life despite the other party's pleas for mercy. As long as 99.9% of the world clings onto these mentalities and the consolidation of power lies in their hands, we will never legalise suicide and there will be no consideration for those who suffer in the way the members of this forum do.