No further explanation given. I suppose pointing out that piece of graffiti is a sly reference to Nash dumping his second wife of many decades for a lady roughly half his 81 years. Consenting adults, whatever. STILL! And then Nash’s comment… never would have pegged him as a fan of the infamous Jazz-rock bandleader, Bond, a gent who basically provided a boot camp for a shockingly large number of Jazz rooted rock stars (you may need to Google or ask Pop pop about these): Ginger Baker, Jack Bruce and Jon McLaughlin among them.
Here’s a post about Bond https://zeroequalstwo.net/graham-bond-the-grooviest-thelemite-you-never-heard-of/
And here’s the NYer piece: https://www.newyorker.com/magazine/2023/05/15/how-graham-nash-still-does-it.