He wasn't doing comedy "on company time". He was working from home during the workday with a note from a doctor (because the stress of the office caused him some medical hardship, as someone with multiple sclerosis), and also on some evenings doing stand-up comedy.
Here's a note sent to him by his immediate manager (who was supportive but cut out of the firing decision):
> Hey Jad, I just want to give you a heads up that somebody within WHYY is agitating about your stand-up comedy stuff. I have gotten questions from HR – in terms of “How come Jad can do stand up but he can’t work in the office?” And somebody even reached out to Bill [Marrazzo, CEO] [...] I have no idea who that person is – or why they are doing this. So far, I have been able to deflect any inquiries, and I said that your doctor is most worried about stress. I said that being in the office causes you stress, whereas stand-up comedy does not. [...]