Old fashioned stirred with ice

Can someone please tell me why classic old fashioned is stirred with ice and then strained out prior to being put in the glass with the big ice cube. The ones I make are simple whiskey, bitters, syrup, orange peel cherry. No transferring or stirring between containers. Every time I have one that is stirred and poured out of its ice It's watered down and gross, and I get p***** about spending twenty dollars