I am a little skeptical of the document that the article links to.
https://secular.org/wp-content/uploads/2019/08/DNC-Resolution-on-the-Nonreligious-Demographic.pdf
There is only the text of the resolution, no header/footer information, no date or logos, no proposer, seconder or any other details other than “DEMOCRATIC NATIONAL COMMITTEE:” across the top.
It might be accurate but it does not look like it is an original document.
Strangely enough, it appears to be a modified form of this resolution apparently adopted by the Massachusetts Democratic Party.
https://americanhumanist.org/wp-content/uploads/2018/11/Nones-Resolution-passed-by-DSC-2018.pdf