Why does Al Capone beat that man to death with a baseball bat in the first place?
I can somewhat see if the man was talking back at him or questioning his motives, but here's it just comes across as Capone acting like a psychopath just because:
https://www.youtube.com/watch?v=Xy3MtznDeqg
Supposedly, Al Capone in real life (or his lieutenants), did in fact beat somebody within an inch of their life with a baseball bat:
https://www.quora.com/Who-did-Al-Capone-kill-with-a-bat
https://mylesdungan.com/2019/10/18/fh42-did-al-capone-kill-three-men-personally-with-a-baseball-bat-as-depicted-in-the-film-the-untouchables/
https://www.mentalfloss.com/article/80310/11-rapid-fire-facts-about-untouchables
But here, if you don't understand the entire context, it really just feels like it was for the sake of shock value to further tell viewers that Capone is the bad guy and how dangerous he is. I also assume that it was meant to show us what Capone will do to his crew if they aren't loyal to him or are being insubordinate.