It appeared he answered his own question:

"Due to safety factors..."

My inquiry was in response to this allegation that one type of harness was "safer" than another.

I guess it would be worth asking why he considers a full harness more "safe" than a half-harness. Perhaps the half harness slipped off in use?

And finally, it says "Don't ask my why", so I will ask the user, not 'my' (whomever "my" is...)