No, it's not a silly question - the thieving that goes on in this country (the UK) beggars belief.
As someone who's spent a good number of years living in the US (on both sides!), I couldn't believe how relaxed people were about their property to start off with. Leaving open-top cars with CDs lying around, sometimes even with keys in the ignition - seriously?? Not to mention having bikes unattended, yet not manacled to something unshiftable, such as a lamp-post.
So yes - if it's not nailed down, you can expect to get it stolen around here. I don't personally know anyone who hasn't had a bike stolen, myself included. It's an absolute blight on the country.
On the other hand, we have vastly less violent crime, and a tiny percentage of the murders that the US experiences. If more than a few score people a year are killed in the UK with guns, it's a bad year. Making it into three figures attracts a lot of head-shaking and gasps of horror from the tabloids.
(The tabloids are another almost uniquely British horror, which - together with The Mail, of course - accounts for most of the brain-rot that bedevils the country.)
This isn't to say the British mate of yours in LA isn't a wanker, of course! Chances are that's exactly what he is. Particularly if he's now living in LA.