True, but if someone wants to get into a house and your neighbor's door is locked and yours isn't, which is the more likely to be entered?
I'm sorry, but your anecdote smells. If you are robbing houses at random, the last thing you want to do is rob an occupied home. You rob an occupied home for a reason specific to that house or the owner of that house.
Most burglaries happen in the daytime when people are at work and their houses would be locked regardless.
And the most common form of home theft nowadays is package theft. Which isn't going to be thwarted by locking your home since, you know, the package is just sitting on the porch.