> 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.
Without derailing this too far further, while we're on reflections it might be interesting to consider what can be read into the virtues or failings of the unbounded punishment camp here.
>Even after having served his time, there's still a certain stain there
In Western jurisprudence the basis for society enacting punishment on criminals is that the punishment is just. One characteristic of that is it that it is proportionate which means it has an end. Criminals who have done their time don't have "stains" or marks as if they're Cain, they have a right to reintegration, because if they didn't, what exactly was the punishment doing?
So no, it doesn't reflect badly on any software project for employing a person who has payed for their crime. It reflects well on any employer if they treat ex-convicts equally.