If the spread is narrow and bid is excessively larger than the ask, the trader is likely trying to hold the price down to make their bid price more attractive. When the spread is very large, people tend to think that the fair price is somewhere in the middle and the bid is not as attractive. The reverse can also be true when they want to make the ask look more attractive. Another popular strategy is to narrow the spread, place an order at the bid, fill the spread in with small orders to narrow the spread, then place alarge order just behind the ask. This baits small orders that come in below the large order behind the ask. The current book looks very much like this actually.

The trader that autofills the book is basically manipulating the perception of a fair price on the book.