Being a parent is one of the most reliably difficult things somebody can do, especially when your kids are babies. Living with a tiny person who has no idea what's going on and relies on you for almost every need is enough of a struggle when you're in your own home, but having to take them on long haul public transport can turn the whole thing into a full-blown nightmare.
This isn't just because you have to deal with it, but also that it can become other peoples' problem, too. Being near an upset baby or toddler on a several-hour long flight isn't a pleasant experience for anyone involved, but not everybody takes the extreme stance of @TB1875. Stating that babies should be completely banned from all flights, not everybody was so eager to agree. Kids might be annoying, but they deserve the same rights as anyone else.