When you use a spit seeder what do you think it will do?
You are going to bring up there thatch or dead grass right?
Also you will be putting down grass seed.
You ask why am I tearing up my lawn ask the neighbors that have NO IDEAL what you are doing. After 20 + years they have no ideal how to care for their lawn. No fertilizer, no de-thatching, no aerification. They call their lawn grass, but it is all weeds and crab grass. The cut it as short as they can.
Now why does my neighbors say I am tearing up my lawn?