It is actually rare that a character is first presented to the viewer as a baby, where we watch him/her grow up so that we can see and understand all of their motivations leading up to the moment they are presented to us. So no, a character is never considered to be a "story elements" that must be fully understood and explained when they are presented within a story.
What fans DO expect, though, are at least rudimentary explanations in regards to plot or character choices that either fly in the face of established facts within the universe that has already been established, or are seemingly illogical as presented and are being sloppily shoehorned in for plot advancement or to trigger feelings of nostalgia.
I don't want to feel insulted by the writer's expectation that I'll be fine with lazy writing, where things that clearly NEED to be explained aren't, and also don't want to feel manipulated by the unnecessary and cumbersome injection of nostalgia berries within the story.
So yes, I'll swallow a "camel"—a noteworthy divergence in Boba's character—if well explained. I'll likewise complain about a "gnat"—a small plot element—if it is glaringly illogical.
So while some folks may like to complain, and at times they hypocritically accept stuff they shouldn't, I don't think all fans can be painted with this brush. I wanted to like the ST, for example, but there's no way I could, and I don't think it had anything to do with me being either hyper- or hypocritical.
