It sounds like your father and others you mention are simply immature Christians who've gotten swept up in the culture around them. These types of Christians often remain immature in their faith for most of their lives and for all intents and purposes appear just like non-believers.

Maturing and growing as a Christian requires seeking and growing and sacrifice. Unfortunately due to the state of modern Christian culture, people who become Christians maybe stop swearing and begin going to church but never mature beyond that point, being satisfied with a watered-down and diluted version of the faith that makes them feel comfortable but not much else. Following Christ is so much more than this, but many never realize it.