So when people like this hear a priest (invalidly ordained) going on and on about demons all the time and how many people are possessed, they eat it with a big spoon.
Yes, I've always gotten the impression that Fr. Ripperger exaggerates the extent of diabolical activity, seeing nearly everything bad that happens as being the result of direct diabolical activity. Sins and character flaws seem to him to be all caused by "generational spirits". So if you're arrogant, it's because of a certain demon. If you're prone to impurity or to sloth, that's caused by another set of demons. Well, a lot of this is just due to Original Sin and the human condition. Maybe someone is arrogant or impure or slothful ... just because they made sinful choices or some of that could be due to natural temperament, etc. He even says that people who have "bad luck" financially are under diabolical attack. Devils don't care about finances. They're rather see people affluent, since as Our Lord said, it's very difficult for the wealthy to enter the Kingdom of God. Demons don't cause sinful inclinations, as it were, against someone's will. They can't. They can only go so far as to try to induce people into making sinful decisions, but can't cause someone to be lustful or gluttonous or slothful.
Generally speaking, Holy Water, blessed religious articles, especially St. Benedict's medals, etc. tend to keep the demons away for the most part.