Eventing has never been free from death and destruction. The concept of safety is a matter of degree.
And I’m not sure how the term safety applies to what happened to Boyd’s horse this weekend.
We can go on and on about pre-existing damage, which may very well be present, but even the studies admit this damage is often not visible through medical imaging. So then what? Do we cancel the jog and instead have all the horses submit to full-body nuclear scintigraphy prior to doing dressage?
The racehorse studies are of a different demographic of horses under a differing set of stressors. These are 3,4,5YO horses galloping on a track. They jog, they breeze, they race. They don’t do dressage or hack out. They’re not done growing. Eventers are older, have dressage training and lots of trot-based fitness work, are used to more varied footing, and are not always full TBs. (It is true that OTTBs in eventing may have left the track due to injury so these might count as pre-existing.)
Perhaps a better comparison would be with National Hunt horses in the UK. Jump racers are older, bigger, fitter, compete over longer distances, work outside on the gallops and jump at speed.