There won't be a way to convince him. It sounds to me like there is just a difference in interests and opinions between the two of you. Which I assume is caused by a large age gap.
The only way he will ever accept your lifestyle is through time. Wait 5 to 10 years and he will see you are a decent human being that works for a living, and that you haven't gone postal and massacred a shopping mall. Only then might he be willing to change his views and realize you are a normal person, but just with different interests than him.
Also:
I don't even like killing spiders, I take them outside instead of squishing them.
I don't kill spiders either. I love spiders and I think they are the best insect ever! I usually won't even take them outside when I find them in the house, because I like to think they will eat the flies, mosquitos, and any other pest that enters the house. I even go so far as to prevent my wife and kids from harming a spider if I can.