Because, to cite Sumate's Aug. 23rd statement...
Sumate has received hundreds of reports of fraud from citizens, civil associations and other organizations [...] Some of these reports have already been investigated and discarted, while others have given rise to more in-depth investigations that will allow, in due time, to demonstrate or rule out the reports of irregularities and to finally uncover the truth.
One of the reports is referred to a series of "patterns" identified in the tallying reports (actas). Sumate is consulting experts and academics in Venezuela and abroad who are carrying out a detailed and exhaustive analysis of these cases. So far, they do not constitute a convincing proof of fraud.
However, we must warn the people of Venezuela that these investigations will take some time.
A legitimate reconciliation between Venezuelans can only come once all doubts about what happened during the referendum have been cleared up.
We deserve to know the truth. If the result is that the winning option was NO, then NO voters must not feel shame to proclaim it and must not remain under the shadow of suspicion of fraud. If the winning result is the SI, it shall be necessary to proceed to the necessary correction to recognize the will of the Venezuelan people.
Deep down, I'm now 99% convinced that there was no fraud and the government won cleanly. However, I can't make a final judgement until I read and consider Sumate's final report. Until then, I'm afraid posting will be light.