I saw someone posted a reactive database just now on HN. I can't believe they didn't think about what child pornographers might do with that. There is literally no discussion of it on their web site. How could it not be a necessary step in building such a thing.
Perhaps part of the disconnect here is not realising how vast the applications are for synthesizing DNA oligos are. It's a very basic thing, and anybody can already basically order them online for a very affordable amount. It's like being worried about someone open sourcing a way to make printer ink.