Your analogy is completely false, because a floor is solid, but cotton threads will compress under the weight of a man, allowing even the areas of the mat that are not covered with threads to receive the diluted blood and retain a print. It's obvious from all three pictures that this is what happened, but it's particularly clear in the CrimeScope-enhanced photo:
View attachment 63119
Further, even if you were correct that no blood would have gotten on the area around the big toe where the threads are missing, it's obvious, as illustrated above, that if the print were compatible with Raffaele's foot, there would be more blood ahead of the yellow line even if only in the area where there is not thread missing.
Finally, do you deny that there's clearly blood on areas of the mat were there is missing thread?