I have my own answer on this but before I put pen to paper I decided to do a bit of research but couldn’t find a decent answer. Lots of words written but no clarity and really no definitive answer. These are my thoughts, for right or for wrong.
The first and perhaps fundamental issue is whether a domestic cat is exposing their soft belly for it to be petted or for another reason. Perhaps, on a lot of occasions, a cat exposes their belly because they want to be on their back, belly up, because it is more comfortable. This is not necessarily an invitation to be petted on the sensitive belly area. It might have nothing to do with a desire to be petted by a human which is why petting it results in a play-fight attack. It is perhaps human arrogance to presume that cats are asking their human companion caregiver to pet them there. That said sometimes confident cats like to be petted on the belly. This may come about over time as part of a human-to-cat routine petting session. The cat has learned to accept it and has confidence in the human’s behavior.
However, a lot of cats like to go onto their back or half on their back. They might do this when they are slumbering and snoozing. They might wriggle and twist and end up either half on, or totally on, their backs. In my experience it is more likely that they will expose their belly partly. It is unusual for a cat to lie totally on their backs with belly pointing vertically upwards. It does happen, however.
In my experience, my cat likes to lie on my lap and then he may wriggle which exposes his belly. This is him being comfortable and I don’t take it as an invitation to pet that gloriously warm and sensitive part of the feline anatomy. If I do pet it I do it very sensitively with deep respect for his sensibilities. If you overdo it you stimulate a play response which leads to play-fighting which in turn can lead to a bite on your hand. This is the ‘attack’ mentioned in the title to this article.
If the cat does present their belly for petting it should be done gently. It may be possible to pet both a cat’s belly and another area which is more acceptable at the same time. This may create an association in the cat’s mind that touching the belly is acceptable. It may make it easier to pet a domestic cat’s belly if two areas are petted simultaneously.
There is a long post on the quora.com website which tries to explain why cats expose their soft belly and then reject the petting. It misses the mark. There is, in my opinion, no scientific, opaque and clever reason to explain this behavior. It’s more about common sense in my opinion.
The belly is a vulnerable part of the feline anatomy. Cats won’t normally like their belly being rubbed or petted for this reason. That’s why I would argue that they don’t present it to a person to be petted. It’s not an invitation for that purpose. They just, as mentioned, like to be on their back sometimes. Other parts of their anatomy which are somewhat out of bounds are the hind legs. In my opinion, domestic cats dislike as much being touched on the hind legs as they do on the belly perhaps even more so. Once again I would suggest that this is to do with self-preservation. It’s an instinctive reaction to defend themselves against possible attack.
We are living, after all, with a wildcat at heart. I would appreciate anybody else’s ideas about this. But please keep them short and sensible. I don’t want to see diatribes and monologues which are so far off target as to be a waste of time.