I can't really entertain the suggestion that pi-holes are considered by Google as a serious-enough threat that they'd go through this trouble just to fuck with it.
Seriously, think about the venn diagram of Chromecast users and pi-hole users. It looks a lot like a tennis ball being dropped into the sun.
Um, the pi-hole wasn't specifically targeted. They just wouldn't accept anything other than Google's DNS. Some ISPs will do DNS hijinks too, like transparently intercepting port 53 traffic and re-routing it.
i don't think its totally unreasonable. the same thing could be said about the people who used adblock back in the day, but im sure google knowing what they know now would never let it thru. im pretty sure they are actively thinking about it now and how to ensure that they can deliver what they want directly to our eyes no matter what. from the position of google everything else would be stupid, im pretty sure they learned the lesion.
Google would certainly be aware of pi-holes and the potential of the threat, but to put things back in context we're talking about a mass-market device which has to deal with bad network config, bad isps, bad routers, etc. What's more likely?
Seriously, think about the venn diagram of Chromecast users and pi-hole users. It looks a lot like a tennis ball being dropped into the sun.