My original, and rather longish post got eaten by the evc monster. This is a massive summary.
You have a point. Unfortunately creationism is centred around the beginning of life, and evolution isn't. That means a 'this vs that' tagline is difficult.
abiogenesis has its own forum with a good reason. While you would be right to suggest it is part of the natural history of life (which is normally explained through the theory of evolution) it is not biological evolution. The clue is in the title. Abio-something is not something that is really on topic when discussing bio-logical evolution. Hence the divide of fora. There is a gray area between chemistry and biology but fora come in discrete packets. There is a gray area between chemistry and physics, but the two can logically be divided into two fora without concern. Otherwise collapse under the term 'everything is physics!'
My suggestion for the tagline, should it be changed?
Biological EvolutionDid life evolve over billions of years from simple forms, or over thousands of years from created kinds?
Apologies for the choppiness, I didn't feel like typing it all out again