These three people have the same goal , they wanna change thier world as peaceful .
But Eren and Light's way is to kill people to make it peace.
Whereas , Gintama knows killing people doesn't take you to anywhere.
Only way is to change people mind.
The way Eren and Light end themselves, atlast they never changed anything.
Ending something isn't they way , right?
That's is why I believe, Gin sama choosed a good and positive way , in which he doesn't cared how many bad things happened around him , he made everyone of them realise.
But Eren and Light's way is to kill people to make it peace.
Whereas , Gintama knows killing people doesn't take you to anywhere.
Only way is to change people mind.
The way Eren and Light end themselves, atlast they never changed anything.
Ending something isn't they way , right?
That's is why I believe, Gin sama choosed a good and positive way , in which he doesn't cared how many bad things happened around him , he made everyone of them realise.