Ed Pierson's own website (the paper's author) says this
Captain Sullenberger has read this paper and said that “it raises many important questions that must be answered.” Dr. Daniel Ossmann, a recognized expert in aerospace fault detection, has also reviewed the paper and “concluded that it illustrates an excellent compact summary of the events and raises concerns that should be thoughtfully addressed.”
Also, Wakner - when you quote Ed Pierson as saying
Some aviation professionals might argue [...] This track record is unprecedented in modern day aircraft
, I think your connection of those two sentences is misleading. What that paragraph says in full is
Some aviation professionals might argue these safety incidents are not statistically relevant and they are just “teething” problems from a new model airplane. They might say these incidents represent a tiny fraction of the thousands of Boeing planes that safely fly millions of miles around the world each day. Although impressive, these big numbers are misleading. It is true that before the pandemic, there were more than 10,000 Boeing airplanes in service around the world flying millions of miles each day. But when the 737 MAX was grounded in March 2019, there were only 371 MAX airplanes in service around the world. 15 safety incidents represent 4% of the entire MAX fleet (15/371=4%). Thus, 1 in 25 MAX airplanes had already experienced a safety incident within the first year of being in service, two of which happened to be fatal crashes. This track record is unprecedented in modern day aircraft.
So Ed P is actually stating his own view that the track record is unprecedented.