Assuming that you are referring to your only purchase in the past three months, I would say that the greatest number of those complaints (both negs and neutrals) are from people who wanted more than the seller was selling.
Complaints about delivery time should be made to the shipper, not the seller; expecting items that are not in the description is fantasizing; an inability to write a coherent response indicates an inability to read a description (especially when the complainant is not working in her first language).
But you are right. Even with a 99.3% FB and 4.9-5.0 DSRs, the customer should read to see if there is a pattern to the complaints. In this seller’s case, there seems to be some problem with speed of delivery, but frankly that is the fault of the post office or courier, not of the seller.