Basically it alludes to supply chain economics. Venice thrived by selling Middle Eastern products, components and other products in the middle east came by way of the Molucca straits from China. If you control Molucca, you control the prices that Middle Easterners and Indians pay for products they resell to Venice, who resells to Europe.

One big reason for the age of exploration and colonization was to acquire Asian products directly rather than relying on Italian and Arab/Turkish middlemen.

Most of the explorers were also Italian, most of them from city states that were major rivals of Venice. Columbus was Genoan, Vespucci was a Florentine, Cabot was born either in Genoa or near Naples, Verazzano was a Florentine...all of these regions were rivals of Venice and had an interest in breaking Venice's monopoly on trade between Europe and Asia. The European powers who patronized them wanted to circumvent the Islamic Empire.

Marco Polo was a Venetian, which also suggests a lot