It's not hard to understand why. Look at the fundamentals. Zion does not have any earnings. They obtain their financials through promoting themselves purely through appeals to Christians who want to bless Israel. This is based on the Word of God:
I will bless those who bless you, and whoever curses you I will curse; and all peoples on earth will be blessed through you."
From this fundamental perspective and based on past experience with Evangelicals who were less than honest, they are encouraged by a skepticism of such operations; the short position is convinced this will fall apart.
It is faith in the Word of God that He will bless Israel at this point in time that brings us here. Ezekiel 36 - 39
In 2012, Mr. Brown made it clear that he could not ask people to continue with their investment if they could not wait till it happens. There was no money, they had just failed with a well, and they knew they had to continue under a new set of rules based on, as Victor Carrillo stated, a more God given scientific knowledge and not on blind faith.
With this all said, from that point, they found their way to where they are today. They honestly stated that they were proceeding with this well on faith that God would provide the necessary funds to complete it, and that happened.
This is totally nuts to anyone in the market and makes this company a perfect short position to hold. Under the normal set of market guidelines, their position is the correct one. This is very dangerous in that they are completely dependent on Zion not finding oil. This turns out to be a Bet they are placing that the oil will not be found.
Now Zion reports that they have positive signs in the form of fractured carbonates where 70% of the Middle East oil reservoirs are found. They are excited about wire logging at this depth and casing the borehole to secure it in order to proceed further.
This is the short position holding to their beliefs while the faithful hold to theirs. They believe they are absolutely correct while the faithful believe them to be mislead.
That's the best I can come up with. Perhaps you have a better perspective.
When you say "very clear covering opportunity" you are speaking as a "technical short" with the benefit of hindsight, which in this case is totally irrelevant because they are "fundamental shorts" who think the stock is completely worthless and should be sold at any price above zero!... A short position can be held indefinitely (as long as you pay any interest due)... Day traders often hold short positions for less than an hour!