With Matthew having finished off the alpha boar, the rest of the ogres were able to finish their fights without being interrupted and they were able to take their time to make sure their targeted boar didn't run away.
Matthew killed the alpha so quickly and unpredictably for the alpha boar that it couldn't even let out a squeal to warn its otherkin to run away or save themselves from the group of people that could certainly kill all of them without fail. But alas, it couldn't do it and now the remaining boars were forced to fight a fight that they couldn't win.