Morbid curiosity or gawkination could explain the attraction.

I believe it does... and in these parts we call 'em "gapers blocks". The traffic could be moving 55mph or 25mph and people will still slow down to 10mph... It's clearly a combination of all four... safety, gawkers, the initial "wanna slow down to help" urge, and being stuck behind all of the above.

...predictable violence in sports like hockey?

In this case, "predictable" only because it is allowed, unlike US "football" where it is "counted on" and other than US *football where us US's count on the fans to take up the slack .

... maybe competitive sports start as a catharcism(sp?)... and if there ain't no violence to "relieve the need" coming from the sport itself, it serves to boil to the surface and erupt the tension into action from the gawkers.

'Morbid curiosity' are just other words for 'genetic predisposition'???