I would take this source with a grain of salt, it doesn't link to any studies, it's from a commercial site, and there are spelling errors. The spelling errors however could be attributed to the author being a non-native english speaker, they claim to be a doctor from a seemingly well regarded medical school in China.
Safe for the stomach rate of alcohol
Any alcohol above 40% of course damages the mucous membranes (chemical burn) [...] Strong alcohol provokes esophagitis, gastritis, gastro-duodenitis.in constant use are formed of chronic inflammatory diseases and are prerequisites for cancer of the esophagus and stomach.
The above statements can be somewhat corroborated, through more reputable sources. The Oklahoma State Government has patrol officer training material that describes how alcohol passes through the body and it's effect. The training is relatively easy to follow and in my opinion, interesting. The takeaway here is that alcohol is not digested. It is absorbed mostly by membranes in the esophagus, the stomach, and the small intestine. The rate of absorption is in part determined by an equilibrium with alcohol and water on either side of the membrane. This means that the higher concentration of alcohol, the faster it's absorbed into your body. This article published in Clinics in Liver Disease, an Elsevier journal, goes over some of the fancy chemistry and largely goes over my head. However it has this to say...
Alcohol has irritant properties and high concentrations can cause superficial erosions, hemorrhages and paralysis of the stomach smooth muscle.
It also says
Peak blood alcohol levels are higher if ethanol is ingested as a single dose rather than several smaller doses, probably because alcohol concentration gradient will be higher in the former case.
So even after drinking the same amount of alcohol you may have a higher BAC, and your body processes higher concentrations of alcohol differently than lower concentrations. It can be rough on your stomach. That said, having a meal before you drink does a lot to slow the rate of absorption.
I believe that most of the concern people have about high ABV drinks, at least in the United States, stems from rumors about moonshine. Moonshine is one of the most widely known high-alcohol spirits. If improperly made it can blind or kill you. Many people don't understand what causes these effects and associate it with the high-alcohol content. However these side effects are usually caused by wood-alcohol, a byproduct of poor distilling technique. They can also be caused by lead-poisoning, which can happen if you make booze in lead pipes. "Moonshine" that you see in the store is regulated and safe.