This is really sad in my opinion, as we should rather support more architectures instead of less architectures. After all, Debian is "The Universal Operating System" .
Now, I know that my opinion doesn't matter much in this case, but many other people who own sparc32 boxes seem to feel the same, judging from the thread which was started by the announcement.
Also, I do realize that nobody wants to retire the port just for fun. To my understanding there is one major problem which needs to be sorted out in order to "save" the sparc32 support in Debian (and also in Linux!):
There is no Linux kernel maintainer for the sparc32 Linux code at the moment!
This seems to be the root of the whole problem. It makes maintaining a Debian port for sparc32 really hard, as you can surely imagine. Also, there seem to be too few people who actively work on the surrounding toolchain stuff (gcc, binutils, etc) which is also very important.
My suggestion would be to not drop the Debian support for now, but rather set the status to "needs help" or something and actively search for contributors and/or maintainers. Heck, list it on Unmaintained Free Software, or write a "call for help" Slashdot article, post the issue on all Linux-/Debian-/SPARC-related mailing lists etc. etc. (or write funny blog posts, heh).
I guess if two or three experienced SPARC developers would step up and take care of the kernel and toolchain maintenance for sparc32, there would be no reason to drop it anytime soon.