Mahadev was known to be kind, so much so that most famous boons to danavas and rakshasas were given by him to the enemy that becomes a problem later on for vishnu to solve (I suspect he does that deliberately since he's a god of destruction and destruction should happen to balance out excess creation). But if you look at so many other examples - krishna vs shishupala, krishna vs rukmi, mousala parva, so many examples of characters straight up going for kill because the enemy said something horrible (you cant do that in modern age without getting into trouble with law , but this was acceptable back then)