A car reviewer's body barely affects the car. A motorcycle reviewer's body is a significant fraction of the total mass and sits high in it, so who is riding changes what the bike does.
The rider is a large share of the moving mass
On a lightweight machine, rider and gear can approach the weight of the motorcycle itself. On a heavy tourer the proportion is far smaller.
That ratio determines how much suspension setup, acceleration and braking feel are altered by the person aboard, and it is why light bikes feel more different between riders.
Manufacturers set standard suspension preload for an assumed rider weight. A rider far from that assumption is testing a machine that has effectively been set up for someone else.
Reach and leg length change the control interface
Handlebar reach, seat depth and peg position combine into a riding triangle. A rider whose proportions suit it will describe the bike as natural, and one who does not will describe it as awkward.
Neither is a fault in the motorcycle. It is a statement about fit, in the same way a shoe size is not a judgement about a shoe.
This is why a reviewer's height is genuinely useful information, and why the better reviews state it before offering an opinion on ergonomics.
Seat height interacts with confidence at low speed
Whether a rider can place a foot securely at a stop affects how relaxed they are in traffic, on gravel and on cambered roads.
A tall machine that one reviewer barely notices can dominate another's experience of it, colouring everything they say about manoeuvrability and around-town character.
Since low-speed confidence bleeds into the rest of the ride, this single dimension can shift a verdict more than any engine characteristic.
Wind protection is aimed at a specific torso
A screen deflects air along a path calculated for an assumed shoulder and helmet position. A rider taller than that assumption sits in turbulent air rather than behind it.
The result is that touring refinement, one of the most heavily weighted qualities in the class, is reported very differently by riders of different height.
Adjustable screens narrow the range but rarely eliminate it, because the adjustment usually moves the top edge rather than changing the airflow shape.
What this means for reading a review
The transferable content of a motorcycle review is the mechanical description: how the engine delivers, how the chassis responds, what the brakes do.
The fit content is personal, and should be treated as a data point about one body rather than a property of the machine.
Reading several reviewers of different sizes, and noting where they agree on mechanics while disagreeing on comfort, separates the two reliably.