As people have commented on all these posts since the incident appeared, we have no info on the incident.

Could be evidence of assault above and beyond that required for self defense (injuries to the intruders back, for example, from him attempting to run away, or signs of the fight continuing from inside to the exterior). Generally self defense is accepted with a good degree of latitude in Canada/(would love to find any examples of cases where someone defended themselves appropriately yet were convicted) , but obvious attacks that aren’t self defense still are assault.