the reason why helmets aren't really enforced is because it's only a danger to yourself. if you fall without a helmet and get a concussion, sucks for you. but in a car, any dumb thing you do can injure or kill someone else.
Are helmets not required/enforced for motorcyclists where you are?
They're a legal requirement here, and you're guaranteed to be stopped if you're not wearing them.
What's not required though, is any level of body protection, like leathers. You could go riding your bike down the motorway at 70mph in just a pair of shorts provided you had a helmet on.
Although police probably will stop you to suggest you get some proper leathers on.