I don’t find them bizarre. Ever been married to a Japanese woman (or any woman for that matter)? They want to have babies at some point in their life. Most Japanese men say no (hence the population decline), and they negotiate down to dogs. Then the wife’s natural nesting and mothering instincts kick in for the dog and they buy all the normal baby stuff. Hence, dogs in strollers. As simple as that.

PS - Almost none of the dogs are disabled. How do I know? They are jumping around the bassinets. Also simple statistical averages.