Why don't you ask the hundreds of priests who are active exorcists today, such as Fr. Ripperger. Go listen to his videos on exorcism on YouTube. He has multiple PhDs in psychology, so he's not some idiot. He does exorcism ministry full-time. Demonic possession is real, and Satan loves it when people deny the power of Jesus Christ through the Catholic Church to cast out demons because it means they're almost surely on the road to Hell all things being equal. Just because most people haven't had a direct demonic experience doesn't mean it isn't real. When you admit possession is real you have to admit a lot of other things too and most people want to bury their head in the sand because it means giving up sins they're attached to. It's a lot easier to outright deny the reality of the demonic than it is to admit your sins and the power of the Catholic Church which Christ founded.