You are of course entitled to your opinion, I know Brandon and I know how dedicated he is, I got to watch him and the OpSec team in action during the Chinese incursion. One of the side effects of being in the platforms group was that I had exceptional access to what was going on everywhere on Google's internal network and machines. And a lot changed after that event, both internally and externally.
I can forgive someone for thinking that if they dug trenches in the street, bought some fiber, and ran it between a couple of buildings, in a country where the rule of law was in effect, they might consider it a reasonable assumption that the fiber is laying in the street unmolested. Even if the distance is such that they can't see the entire length of the ground above the conduit.
Prior to Snowden's disclosures, it was the common belief amongst the security community that in 'safe' countries, the government in power would not subvert your infrastructure through physical access. They might do some network tricks, but not tap your fiber. In 'bad' countries counter measures were taken. And the network setup in say Russia or China was different than it was in the US and the UK. That your own government would illegally subvert your infrastructure [1] through the use of a technicality was not considered a "likely" threat [2]. Given that not it has been exploited it is rewriting a bunch of assumptions. I am not surprised in the least that they are now deploying the same hardening they use in hostile environments world wide.
[1] The NSA cannot legally tap into communications infrastructure in the US (that is the FBI's job) and when the FBI does it they need a warrant. By doing this in the UK they sidestepped those constraints.
[2] In classic vulnerability analysis you deploy your resources against both the probability and damage potential of a given threat. So for example datacenters are vulnerable to being bombed by aircraft, the probability of that is low enough that you don't defend against it, bombed by cars you put a security perimeter around the building.