I dispute that they do but regardless a political statement is not the same thing as a profession of religious tenets.
It should be obvious why, but if not consider a future where the SQLite team needs to replace a member. What's the plan if the best candidate is an Orthodox Jew? Are they going to update the CoE to read:
>The founder of SQLite and all current developers, except for Ruth Cohen, have pledged...
Even if they're the nicest and most welcoming Christians in the world and will make a better change without hesitation it's still presents a disincentive for non-Christians. There's simply no place for that in any professional setting.
For some non-Christians.
Some of us non-Christians are open to reasonable people of every persuasion.
The CCCoC presents a disincentive to non-progressives or progressives who just happen to disdain identity politics and the race to the bottom in search of ever more fine-grained intersectional levels of oppression that involves.