In general we (KDE) don't just delete bugs.
There was talk about deleting all open arts bugs, since this is basically
unmaintained since some time already and doesn't exist anymore in KDE 4.
There is a team of people going through bugs.kde.org and checking whether
bugs are still valid and close them if not.
Sometimes bugs are closed if the reporter doesn't respond anymore and the
developer can't reproduce the problem.
I don't know your specific case, but in general, we don't just delete bug
You wrote "talking about simply deleting". So they were actually not
deleted ? Maybe just somebody had a bad day when proposing this.