It's going to depend on a person's perspective. People commit suicide for all sorts of reasons. Some may do it because they feel they failed at life. Others because life failed them. They never got the breaks or support that would have made the difference. For others, it's definitely a 'success' if they were suffering with no other means of stopping that suffering.
I think it's mostly seen in terms of representing failure by pro-lifers though- a 'cowardly' act, 'the easy way out', yada yada yada. Presumably because they believe people ought to be committed to a life they didn't choose to participate in and ultimately, only have so much control over. Presumably to them- the end goal of staying alive is worth more than anything else.
I sometimes wonder whether it's wishful thinking that leads them to believe that. That everyone can in fact be helped to live a happy and fulfilling life- no matter what ails them. That seems pretty naive to me. Surely they must realise that some problems can't be solved or even mitigated all that well. In which case- the only conclusion there is is that they still expect people to hold on- even if they are in pain/ struggling. In which case- I wonder where their empathy is.
My personal view is- suicide can be tragic- in terms of- a person found they couldn't live a sustainable life here. Is it because they failed to try hard enough? Perhaps but then- why was that? What held them back? Probably a whole bunch of stuff they didn't have much control over- illness, abuse, misfortune. Why is it automatically expected of them to be utterly resilient to every shitty thing life throws at them? It's not to say they wouldn't be happier if they could learn to be more resilient but, that isn't easy for everyone.
Ultimately though- suicide is a rejection of life and all that it imposes/ expects of us. Personally- I think we do have the right to reject life. We didn't choose it after all. That was our parent's decision. What other thing in life- even things we did actually choose eg. a job or marriage are we expected to be committed to forever? Just about everything else now, people will accept it's our right to choose on.