In the Vim help a paragraph is defined as follows: "A paragraph begins AFTER each empty line..." This implies that the empty line is not part of the new paragraph but belongs either to the previous paragraph or is not part of any paragraph. However, the command } supposedly takes one "to the beginning of the next paragraph". Since this command positions the cursor ON the blank line this implies that the blank line does belong to the next paragraph. Otherwise, one would expect that the command } would position the cursor at the start of the text, and not before it on a blank line. How is one to account for this?
No, the blank line is not part of the paragraph. You could test this with dip
which will leave the empty lines alone.
} does not move to the next paragraph, it moves to the first position after a paragraph, which in your case is a newline.
It is a exclusive (:h exclusive) motion, which means, that it moves the cursor further than the block. If you use d} the newline will not be deleted.