What country's sea captains found plundering other country's ships more profitable than establishing colonies?

it was England ...

The correct answer is "English Sea Captains".

During the Period of colonization of the Americas in the 16th century, The crown of Castille (the Spanish) were the dominant force throughout the Caribbean, as they had the first-mover advantage for having funded the first expeditions to America. At the time it was well known that there were profitable gold and silver mines in this continent and it was common to find ships carrying these precious metals crossing the Atlantic.

On the other hand, England and France were going through a relative period of peace which let their societies develop at a rapid pace. Important developments in naval technology were made. However, there were no conflicts to be fought.

Fueled by their ambition, many English sailors decided to abandon their current economic activities and engage in Piracy in the waters of the Caribbean leading to the era of Pirates, which extended from the 16th century until the beginning of the 19th century. It had its peak in the 17th century.