Swizzle Sticks

The origins of the Swizzle Stick can be a little murky, and perhaps results from the conbination of a couple of different sources.
In th 1930's in the US, a Swizzle stick was a gadget used to remove bubbles from sparkling wines. I have so far found little reference to this usage, so I'm not quite sure why folks would be wanting to de-bubble bubbly.
There was also a device known as a Swizzle Stick in the West Indies that was used to 'Swizzle' ice and liquor together in a jug or glass to create a frost on the outside. Originally it was made from the dried stem of a tropical plant with a few small branches left on one end.
And T=there is a type of drink known as a Swizzle which consists of spirits, citrus (lemon or lime) juice, sugar (or other sweetening agent), soda, and often a dash of bitters. It can be madein large pitchers filled with ice, then served in ice-filled highball glasses.
So, as you can see, there is are a couple different directions this can go. I'm not sure when the drink known as a Swizzle came about, or if it originally had any connection to the swizzle stick at all, but it could easily be seen how the two identical names could have come about on their own, then naturally melded together when it suddenly was "assumed" they were supposed to be.
As for the use of Swizzle sticks in cocktails, sometimes they are simply a type of garnish or decoration, but often they do serve a purpose. A Swizzle stick should almost always be added to a drink that is "built" in the glass. Meaning that either the ingredients are poured straight into the glass without shaking, or only some of the ingredients are shaken together ahead of time, the rest being poured on top once it is in the glass.