Even if you're an incredibly skilled and careful rider, there are a multitude of accident types that are just completely out of your control. If you hit a diesel spill on a roundabout, the outcome is pure fate. Defensive riding only gets you so far - staying at home is the only realistic way to defend against the possibility that the driver in the next lane will spill his coffee and swerve into your path, or a driver waiting at a junction will abruptly pull out in front of you because he wasn't looking.

At least as importantly, the consequences of accidents are vastly magnified for motorcyclists. I know of people who have died in relatively low-speed crashes because they were unlucky enough to slide straight into a piece of road furniture or land head-first on a kerb. If you look at the accident statistics, a large proportion of fatalities and serious injuries involve low-powered motorcycles travelling at ordinary speeds on ordinary urban roads.

https://assets.publishing.service.gov.uk/government/uploads/...

https://www.gov.uk/government/statistics/reported-road-casua...

> driver in the next lane will spill his coffee and swerve into your path

You can significantly reduce that risk by simply staying away from others and avoiding situations with a large speed differential. If the lane next to you is going 20mph, don't go 40+ next to them.

There are a lot of these things you can do, that most people don't because "it's not their responsibility".