The boys almost act like they're pitching to a casting director rather than wanting to join the army.
Why the boys don't logically join the Navy (bring merchant sailors already) is left to the viewer to ponder upon. With the advent of WW2 5 years later, however, both characters would be busy supporting the war effort---in the Navy.
One of a number of Popeye shorts which were sent off to Asia in the 80's to undergo the infamous redraw and colorization process.