guy describes trespassing as fine then accuses homeowner of murder logic

Just as a note which may slightly alter your view here. The teens in your first example aren't trespassing. They have not been asked to leave or jumped a fence or anything. They have stepped onto the curtelage of the property and have not been asked to leave. Much like a city worker stepping onto your property, many people see that as a form of aggression and threaten the city worker with violence, creating a disproportionate response to a benign action. The only aggressor in that scenario is the home owner, and they are only aggressing because they perceive to be aggressed upon. Your mistakenly believing the teens were aggressing in the first scenario speaks to part of why proportionality in law matters. It can hopefully chill what individuals may believe to be appropriate responses when in reality they are completely disproportionate due to misunderstanding the situation. And in your view it seems that you would be okay with the teens straight up murdering the home owner because the teens were agressed upon, is that correct?