simply put - because i want to make a beer that is close to that original beer.
of course there's a ton of reasons why any individual might want to do that. these reasons my or may not be acceptable or understood by you, but they are to that individual.
its homebrew. its my beer, my way, for my reasons.
I've only done 3 batches - my second was an Old Speckled Hen clone.
for some insight as to why.
the girlfriend likes OSH, so I thought I'd make her something she'd enjoy. I also like it.
I rarely find OSH around here, and when I do, its in clear glass and often not good b/c of it(skunked).
Now I've got a foundation to work from. If the recipe is good, I'll use it again. if it needs some tweaking, I'll change somethign and see how it works. repeat ad nauseum until I've got it nailed down where I want it.
Being new to brewing, I've got to start somewhere. clones, ingredient kits, and others recipes are the best place to start. As experience grows, I'll learn more and more about he process and ingredients and start doing my own thing, but even then, the mood will likely strike me to make a clone, and then 'improve' it, atleast in my eyes.