Recommending them means nothing at all. That is practically the status quo when breaking up with another business, employee or whatever when it is done publicly. (and this obviously had to be public)
Why not take his statement at face value? He's personally reliant on ad income from his site, as are several of his friends, so it makes sense that profiting off an ad blocker makes him uncomfortable. No conspiracy needed.
(For background, see: http://www.marco.org/2015/09/17/why-peace-blocks-deck-ads)