Mac 10.6.8 cannot run Alpha or Beta versions of Minecraft

In one of Ethoslab's videos, he explores his old Minecraft Alpha worlds.
This video made me want to play Minecraft Alpha myself, However, I was not able to run the older versions. Please help!

I am currently using Mac 10.6.8. I also tried to play the older versions after deleting everything in my Minecraft file (Such as my Versions and Worlds files) and I re-downloaded everything.

I will include my Dev Console page.