What else do you turn to when you've tried and tried and tried to make a name for yourself, but everything you have started has ended in failure? - you turn to attacking others to make up for your lack of success.
Leo acting as if running a bar that plays music that appeals to people over the age of 60 is a success. We all know that bar will eventually close and he will, like he has before, open another - it's a never-ending cycle of self-appreciation and dreams of grandeur.
Leo's theory is that unless you have done it yourself, you're unable to have an opinion on the matter that holds any weight. In that case, we wouldn't have political commentators or critics of most natures - yet we have Leo, who has to race horses under his sisters name because he's a failure.
What a sad human being.