Members help other members with technical questions and problems using Writing.Com!
Since you asked for advice --
You seem to have several misunderstandings about how the site review system works.
The rating is a tool for researching your audience and is about the reviewer's experience of your item. It's not intended to measure the quality of your item. You as the writer of the item never get to specify what the rating will be. An item's previous ratings do not dictate what the rating should be either. The rating is always the reviewer's prerogative. It's unrealistic to expect every reader to love your writing, and getting a review with a 4.0 star rating doesn't change anything about a review from someone else with a 5.0 star rating.
When you have your items set to accept reviews from any member of the site, you as the writer of the item do not get to specify what kind of review you get. That is the reviewer's prerogative.
If you have personal requirements about the kind of reviews you want, then you need to do the work to set that up, which may mean making your items available only to a review exchange group.
As a writer, antagonizing the readers who like your work is a self-defeating and unprofessional behavior, especially if they like it enough to read more of it. If it were me, I would thank him for his comments and probably send along 100 gift points (I send a lot more for in-depth reviews), forget about it, and go about my day. The gift points are for the value-add to the item: by rating the item, the reviewer moved it up in the default site search results. In other words, an item with 1 5-star rating and 1 4-star rating ranks higher than an item with 1 5-star rating.
Anyone who is writing reviews that short is not getting automatic gift points from the site for their efforts except perhaps from the Review Mixer for their first review to you, and for that review, you also receive gift points. If they have opted out of the Review Mixer, no gift points are given to either of you.
That said, if getting such reviews is still going to ruin your day, you're free to go ahead and block the member.
Hope that helps.