When Jon Garvey wrote, “No it isn’t. Next topic please.”, that basically sums up my reaction as well.
Of course, I have no problem with acknowledging that “historical Christians” down through the centuries did have a range of viewpoints on secondary issues like infant sprinkling. But the deity of Jesus Christ is a primary issue and has been a point of consensus among “historical Christians” for 2000 years. It matters.
Over the course of my career I got to know a lot of “first-rank Christian theologians” and I am very familiar with their “mainstream scholarship”. So I tend to yawn a bit when someone makes bombastic claims contrary to my personal experience in the academy.