I am the one who originally pushed for expr license change, and contacted apple, and the original expr licensees, etc....
here's what happened, in summary, from my foggy memory:
i contacted the original author of expr, Mr Yadegari, and explained the situation that expr was in a strange limbo between vanilla pd and pd-extended. It's included in vanilla, but there license is different, etc etc...
When we looked into it, we found that the original license for expr was in fact LGPL, not GPL, as stated in the pd documentation. (So, as Iohannas suggests, a bug report might be a good idea)
When i asked about the possibility of changing to the pd style BSD license, Mr Yadegari was totally fine with that, and said that is what he had wished anyway.
However, the expr license was now under control of the university, and i would have to contact the relevant people to ask about changing the license to BSD.
In the meantime, i had called Apple, and asked about the legality of GPL, and they said GPL was not permitted, as you need to release the code with the app, and they don't have that facility built in to their app store. Then when i asked about the possibility of LGPL, which doesn't need the source code included in the package, they sent me from person to person, and i never got a straight answer... basically they told me that if i wanted to use LGPL, i would have to hire a lawyer to speak with their lawyer.
So....it seemed like changing the expr license to BSD would be the best option.
I contacted another developer who Mr Yadegari referred me to, and we spoke about the possibility of changing the license. He said no one had touched expr for years, but couldn't see any reason why not to change it. He said he'd need to check with the relevant department at the university, and with the other developers who had taken on the caretaking of expr.
And then, university summer holidays started, before i could go any further, and i never heard back again about the license.
So, as far as i understand, the expr developers i spoke to all seemed fine with the idea of BSD, but we just never got as far as getting everyone together and making the change.