I find the answer to this question is so awkward and so meaningless. Please explain what it means

Retailers reported moderate gains in their November sales, as much because of their sales of a year earlier being so bad as that shoppers were getting a head start on buying their holiday gifts.

Underlined portion:

of their sales of a year earlier being so bad as that.

Answer:

their sales a year earlier had been so bad as because

"because" here is as vague and ambiguous as the original !!!!!!