> Should his contributions to open-source projects be rejected?

As someone whose attitude towards open-source is that it's the code who should do the talking, and not who contributed it (nor the colour of their skin, or their sexual orientation, etc) ... I'd say he should be able to contribute code, as long as the code is good enough. Same rule as every other code-contribution.

But the Debian-project has made the decision to elevate him and have him represent Debian at conferences like DebConf, and that strikes me as something some people might find more objectionable.

Even after having served his time, there's still a certain stain there, and it's up to the Debian project to what degree they want that stain to reflect on them as well.