This article plausibly explains that Giuliani’s behavior is calculated and not just crazy:

Here’s the Real Reason Giuliani and Trump Are Admitting to Paying Off Stormy Daniels

Key ‘graph:

So why are Giuliani and Trump positioning themselves for an FEC investigation and fine? Apart from diverting the news away from the Mueller investigation, Trump can tweet a big ‘so what,’ because, as it turns out, other campaigns—including Barack Obama’s 2008 effort—violated FEC rules and faced big six-figure fines.

It always comes down to whataboutism with these people.