The workshops are not his day job, and he doesn't make any real money at it - he just does it because he loves it. Unfortunately that means some of the emails fall through the cracks.
Honestly it goes both ways.... I've experienced high level practitioners without all the unprofessionalism. You don't put an email address on the internet asking for emails of interest then not simply hit reply and say 'no'.... 'or yes if not enough of the people I like come'... or whatever.
Is the email address good or isn't it? For some reason the phrase "piss poor" comes to mind. I realize I may be ostracizing myself with this comment and so be it.