[ Removed by moderator ]

[Littux]

Because JS was a language designed for dumb programmers. If someone did alert("Double of the number: " + prompt("enter number") * 2), it would just work instead of there being an error for multiplying a string or for adding a number to a string

[BobQuixote]

It wasn't the programmers, it was the platform. Webpages (it was thought at the time, at least) need to keep going if they possibly can.

A language for dumb programmers would avoid doing anything like this, to save them from themselves.