I have to avoid GPL and LGPL code like the plague because I have to release close-sourced commercial software for my employer, and look for BSD licensed code for my own software because I have to eat.
It's an interesting statement to make! I think both GPL and non-GPL have their merits and good/bad points, but I have worked hard on something and don't want to give it away. Stallman would likely steal the bread that I had taken to put on my table then.
You are depriving your users of freedom by releasing closed-source software.
I have heard Stallman literally say that stealing food is bad, but working on proprietary software is worse.