That's a horseload of bullcrap. For a start there are plenty of pickpockets in many spanish cities (not just Madrid, Barcelona and Valencia). Then there are people visiting houses: don't tell me it doesn't happen for I had my house visited by thieves the one time I forgot to put the alarm on (because I had to run to the ER for my daughter was between life and death).
I happen to know both Spain and Japan very well (I've got family in Japan): there's not anywhere near the level of safety you have in Tokyo in spanish cities.
Not even close.