Actually, TrogJoe, a slash with a scimitar would have made a swifter and cleaner kill than a straight sword, because the scimitar's strike point would have a lower surface area. A straight sword would have involved more hacking, because the pressure would be spread out on the blade.
Secondly, Armas, it was the Navy that adopted the scimitar first because they were practical for close combat, which was ideal for boarding an enemy ship, or for defending against boarding. A thrust with a scimitar properly done was very difficult to parry with a European sword, considering that just rotating the scimitar horizontally could be deadly.
Pirates were around long before the Islamic Empire, and the Viking era saw some pirates too.
But you raise interesting issues of what we understand about scimitars, the Islamic empire and "Eastern" swords.