What should I do with my aggressive cat?

if you must lock kitty up, the garage is the most dangerous place to put her, put her in her crate or lock her in a bedroom. the garage is very hot, your car,antifreeze,oil, paint, chemicals and all kinds of dangers for your cat are in there.i wonder if they come in and try to force themselves to pet her? if so, thats why they are getting scratched.she is only 3 so i doubt there is any dementia going on. i think she is scared of the neighbors and they work too hard on getting her to like them. cats sense things about people. if they would just come in, put the food and water out and freshen up the litter box, i highly doubt anyone would get bit or scratched.i think this is a people problem more than a kitty problem.