Circa 2009, while attending graduate school at the University of Minnesota, I was a student of Dr. Nick Hopper, whose CS research team were intensely focused on ways to deanonymize TOR traffic using an impressive variety of techniques. One that stood out was using statistical analysis of netflow to correlate browsing patterns. Considering that last-mile bandwidth providers also gather netflow and often provide flow data to three letter agencies, being able to map flows from known exit nodes to last mile service providers isn't rocket surgery. After an early initial exposure to some of their research, I never placed any trust in TOR. I still have a quote from Dr. Hopper on my laptop login screen, to serve as a reminder: "The problem with privacy on the Internet is that people believe it exists."
Tor specifically doesn't resist pervasive flow monitoring, and their lack of being able to resist that attack is discussed thoroughly in the documentation, at least twice (both general usage and in the threat models section).
The attack you say stands out is literally just implementing the most obvious thing that Tor explicitly doesn't defend against. It's just a demonstration that Tor's threat model is accurate, and not a weakness in Tor that people were unaware of.
The you had a knee jerk reaction to not use Tor for what it's good at when you realized it can't do everything is the all-or-nothing, it must be perfect mentality that is the enemy of good.
It's people like you, with your all-or-nothing extremism that undermine reasonable discussions about partial steps we could take.
