The manual continues...
"Immediately blow the chain dry with compressed air after cleaning.
Complete cleaning and drying the chain within 10 minutes"
Motorcyclist interview with PJ1 CEO....
"MC: What about cleaning the chain? Almost all the OEMs and chain manufacturers recommend cleaning the chain with kerosene.
PJH: First, some kerosenes can, I think, affect the O-ring itself. Secondly, kerosene can leave a film, and that makes it more difficult for the chain lubricant to attach itself to the chain's surface. Naphtha [used in some spray chain-cleaners] can also leave a film.
MC: So how's an owner supposed to clean their bike's chain?
PJH: Well, if there are some commercial products out there--and a lot of people use our Super Cleaner for that--that can remove the dirt but not leave a residue, that's the key to the whole cleaning process without damaging the O-rings or undermining its seal."
Regina chain website.....
"When the accumulation of dirt on the chain (sand, mud, asphalt particles or other foreign materials) is excessive, the chain must be washed with a brush and kerosene. After washing, the chain has to be dried immediately with a jet of compressed air."
So it seems there's a possibility of damage using kerosene if not completely removed, or if allowed to remain in contact for an extended period.
Before your criticize someone, walk a mile in their shoes. That way, when you do criticize them, you're a mile away and have their shoes.