Well, the reason they didn't think nobody was home and leave is that they had a pretty good idea that someone was there. It turns out they were right. So I wouldn't complain too much about that.
I have no idea if they had reason to believe this person is violent. Of course, any effort to enter a home carries some risk, so it's better to be let in peacefully. However, I'm also assuming they didn't think they'd find any evidence or else they wouldn't be shouting at a building for an hour, tipping him off that they were there.
Overall, it doesn't sound like the most professional of police force, but it could also have been far worse.