Baby Tea said:
I think it all comes down to presentation.
I haven't seen an original film in...well, ever, really.
Even the greats share themes and characterizations from other films, or books, or plays.
But that's not bad. It's all in the presentation. A tired theme or idea can be made fresh with the right presentation. If you can present it well, then it even old, worn ideas can be renewed as something fun, awesome, and/or entertaining.
I have to back that up. I don't have a problem with a fundamental lack of originality (storytelling is heavily reliant on formula in most cases anyway) as long as there's
something fresh that's of merit.
A proven narrative framework can still be effective, it's just a matter of transcending its inspiration, or at least giving it a different appearance to avoid accusations of a derivative nature.
This desire to acknowledge, or even mock borrowed story elements/structure that we recognise is a peculiar trait of our media saturated culture. We draw parallels between media items we know of, and for some of us it's a little distracting but some seem to be outraged by it. Some mocked the Star Wars visual borrowings of the recent Dr Who specials, ignoring the timeline of explicit influences on that franchise like Kurosawa, the old westerns he mimicked, and of course, the monomyth. Of course, some similarities are easier to spot than others due to the prominence of the source.
So, in answer to the OP's question, I don't know, or even understand why people have that reaction. Plot alone isn't the only worthwhile factor of a piece of media,and great things can be done within well-worn structures. Maybe it's just a case of the product being arresting enough to distract from a fundamental lack of originality.