That seems extremely petty if true.

FWIW, https://en.wikipedia.org/wiki/History_of_web_syndication_tec... notes that Atom was a side-effect of RSS being frozen. Also FWIW, Dave gave Atom (then Echo) a tentative early endorsement:

"If and when it reaches closure, I will recommend to UserLand that they support the format, both for input and output, and I will help to the extent I can to write drivers for the software. I will continue to answer questions for the people working on Echo, and offer my opinion when it appears to be welcome, but will step back when it is not." — http://backend.userland.com/2003/06/26

And, true to his word, Dave added support for Atom in UserLand products in 2007.