The misnomer that sibling rivalry is a thing of the 'past' history- wh

The misnomer that sibling rivalry is a thing of the 'past' history- where brothers slit each other's throats in a gory race to kinghood - can and does not seem appalling; but still does.

While reading the question stem, we see that a portion of the sentence is dashed. This is called an "em dash" or a "dash" and it replaces commas, semicolons, colons, and parentheses to indicate added emphasis, an interruption, or an abrupt change of thought. The info provided between the dashes gives additional information about sibling rivalry. For convenience, you can ignore the same. The construction is now as follows.

The misnomer that sibling rivalry is a thing of the 'past' history can and does not seem appalling; but still does.

Further breaking it down (or rather expanding it - by placing the omitted verb + object)

The misnomer that sibling rivalry is a thing of the 'past' history can seem appalling, and does not seem appalling; but still does.

A. can and does not seem appalling; but still does.
can seem appalling and does not seem appalling - doesn't make sense.
B. can and does seem appalling; but still does not.
can seem appalling and does seem appalling; but still does not - doesn't make sense again
C. should and does seem appalling; and still does.
should seem appalling and does seem appalling; and still does - Good enough.
D. can and do not seem appalling; but still do.
can seem appalling and do not seem appalling - doesn't make sense again
E. may and does seem appalling; but still doesn't do so.
may seem appalling and does seem appalling; but still doesn't do so - wordy (after semicolon) and doesn't make any sense.

I have no idea what the sentence is saying...

Convoluted sentence with several negatives. But considering that ‘can’ means capacity, the combination can seem appalling looks dubious. Does the word ‘sibling rivalry' have the capacity to appear shocking? After all, sibling rivalry is no more than a word. So why it is a wrong name or why it should be shocking is anybody’s wonder.

So I think 'can' does not a have a locus standi in the circumstances. So I make bold to dump A, B, and D. Between C and E, I would prefer C because E uses ‘but and still’, a redundancy.
Incidentally, what does ‘past’ history mean? Is there a present history or future history?

Unfathomable question.
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Severely flawed question - the part after the semicolon must be a complete independent clause. Hence all options are wrong in the first place. The relative pronoun "where" must refer to a place, not "history". In GMAT "should" indicates a moral obligation. "Still" introduces a contrast, but in OA (C), there is none.

There are too many errors in this question - it seems to be from an unauthentic source.

This is not a good one! The subject of the sentence is "misnomer," so what seems appalling is the misnomer, not the action? That makes no sense. There is also no misnomer in this sentence. (Look up the word.) What else? "'Past' history" is redundant. "Where brothers . . . " follows "history" and so should be modifying that, not sibling rivalrly. Then, as Aditya pointed out, we should have commas in place of semicolons in every answer choice.

I could probably go on, but in short, do not try to learn English grammar or GMAT SC from this sentence!
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The misnomer that sibling rivalry is a thing of the 'past' history - where brothers slit each other's throats in a gory race to kinghood - can and does not seem appalling; but still does.

A. can and does not seem appalling; but still does.

B. can and does seem appalling; but still does not.

C. should and does seem appalling; and still does.

D. can and do not seem appalling; but still do.

E. may and does seem appalling; but still doesn't do so.

misnomer suggests contrast in meaning.
Sth seems sth but it does not.............................is the structure of sentence.

so ignoring the additional info about past history in the form of modifier.
The sentence is

The misnomer that sibling rivalry is a thing of the 'past' history can and does not seem appalling; but still does.
misnomer reg sibling rivalry is singular subject and needs a singular verb does not plural verb do.
so D is out.
and in option C does not indicate needed contrast. hence C is out.
can and does seem are parallel wheras can and does not seem are not parallel.
so A is out.

Misnomer seems appalling; There is no action or event to say mis does not do so.

but still doesn't do so in E does not make sense.
So B.

Correct me if I'm wrong.

Please provide a step by step explanation to this question. Why is E wrong ?
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I dont see what is the misnomer in sentence ? This can and does not seem to be a GMAT question.

can someone please clarify if the question itself is correct?