I'm of the mindset that code written 20 years ago should run today. This is a breaking change on a critical piece of internet infrastructure. Google, by nature of operating the most popular web browser, has a moral obligation to the community to provide a stable environment.
There are something like 10^9 webpages out there. How many of these will become less accessible because of this change? Many well maintained webpages will have to expend resources to migrate off ftp. Less maintained webpages with FTP links will not be updated and put the burden of installing an FTP client on the user, reducing accessibility.
This is Google externalizing the cost of updating their software by forcing everyone else to update their webpages to following Google's specification.