Mine's like that, too. It does seem a bit odd - my only guess is that they do it on the cheapy ones because the switches aren't really up to the job of lots of momentary switching, and would quickly burn out.
re. handle, maybe ask on freecycle and see if someone has a dead grinder with a suitable handle? That or take the remains into a DIY shop, find a nut that fits the thread, then use that to determine the right kind of bolt to use for a replacement handle.
cheers
Jules