The word "tomfoolery" means something silly, foolish, and stupid, silly, and not serious behavior. Tomfoolery is synonymous with the word "fandango" which is a slang for stupid and silly behavior. For this reason, we can appreciate that the word "tomfoolery" in the excerpt given in the question means silly behavior, so we can rewrite the excerpt as You can walk and talk, so why don't you stop this silly behavior and become a cowboy like the rest of us? "...
Yes, the ideal that every US citizen should have an equal opportunity to achieve success. Through prosperity, through hard work, determination, and initiative.
