Attacking enemy players is a valid mechanic and is not considered toxic behavior.
For example during the glorious first of June events
Vanstabel convoy 170 - ships captured 40 british prizes on its way to France. You might consider it a realistic mega gank fleet.
Howe fleet also captured a lot of smaller vessels, including unarmed traders with no combat experience.
During napoleonic wars a lot of frigate captains received promotions for capturing multiple smaller prizes.
That small vessel could be carrying precious exceptional frigate drawings or repairs for a damaged fleet which will later sink you. Delaying it might help you defend a port. But at this stage there is no cargo and attacking a lynx gives no rewards to high level players. The reward is the fact of catching and sinking someone, and apparently it is good enough for some.
BUT if the player is griefing then it is bad and should be reported.
As far as I remember no ship can catch a Lynx in instance. Ow curves are getting fixed this patch.