I thought the key ingredient of astroturfing is the concealment of the source of the message. The idea is to make a centralized effort appear to not be centralized. I would say that providing templates to contact public officials would qualify as astroturfing. And yes, I would extend that attribution to many advocacy groups whose proposals I agree with.

It may seem similar enough, but that does not seem to match the standard usage[1], in which the critical ingredient is the false impression of pre-existing grassroots consensus.

Telling the existing John/Jane Q. Public, who already agrees with you on the issue, to actually do something based on that agreement, is just regular activism and doesn't connote the "aha! caught you" aura of an astroturfing allegation.

[1]https://en.wikipedia.org/wiki/Astroturfing#Definition

I think he's trying to say it's not astroturfing - ie that is too large-scale for that. Thereby preempting dismissal of this anecdotal evidence.