Tl;dr - It depends, the questions are vague.
Some commenters have picked up on these issues, but the title and questions posed are not well defined. More ambiguity arises because some of the question is premised on whether people have the right to end their life. Some of the question is premised on whether suicide can be bad (not the best course under the circumstances) or wrong (in a moral sense).
In a vacuum, suicide is not good or bad or immoral. It just is. Context matters.
Of course, whether one has the right to do something and whether something is bad or immoral are two different concepts. One can have the right to do something, yet that something can still be a bad or immoral thing. We have the right to eat only pure sugar. It still is bad to. We have the right to not tip a good server at a restaurant. Still, it's wrong not to. We have the right to buy up affordable housing units, triple the rent, and evict those who cannot pay. Still, it's wrong to do so.
Because context matters, suicide can be relatively good (as in, better than the status quo, though these are all tragic cases) or bad (a poor choice) or even immoral (think abandoning dependents or using a method that involves others without their consent).
Quantitative studies that look at suicide show us, based on failed attempts and survivors' future acts, that many attempts are made when suicide is not the best option. Anecdotal evidence from this website is consistent with that. It follows that many suicides are likely "bad," in that they were unnecessary and not the best course of action. Some suicides are even wrong (though the mental state of the suicide may excuse a harsh moral judgment of the person, as opposed to the act).
Do people have a right, even in the depths of despair and despite being not fully informed, to decide to end their lives early? Sure, but that choice can still be a bad thing and sometimes even wrong. The only way we can conclude suicide is never bad or wrong is if we take the position that our actions only matter to us. That would be an ironic position to take here, given how many here identify their pain as caused by others' actions.