I'm just curious- Why would you want to specifically avoid the GPL?

If you look at it through the eyes of the GNU people, you're making an active choice any time you use software. By using GNU software, you're supporting the FSF and the GNU project.

Some people would rather support the BSD license instead.

Other people just don't care at all.

The same way there are people that want their entire software usage to be GPL/MIT/BSD/etc, there are people that want everything to be non-GPL. Unless you are going to be hacking on GNU Screen and feel the need to do something that the GPL forbids, there's really no reason to stop yourself from using a software package just because it's GPL-licensed.

I think it's ironic that your argument is remarkably similar to "nothing stops you from using a closed source program unless you planned to start hacking on the source." Sometimes you don't know when you start using something what amount of hacking may be required.

Yes, but you can contribute to GPL-licensed projects. It's just specific things that you are limited in. We're talking orders of magnitude. 'closed-source and GPL' and 'MIT/BSD and GPL' aren't even in the same ballpark.

One thing you can't do with a GPLed application -- and something I do all the time -- is try to support copyfree licensing rather than copyleft licensing.