Mental illness are real, but there are medications which can taken or meditation techniques employed to treat anxiety etc without turning a flight into a petting zoo like they have in the USA.
Very true. This current case is exactly about that. She wanted her pet to sit next to her on the flight. Nothing more, nothing less.
The argument for need of anything but a genuine guide or assistance dog on a flight is tenuous as best, and as someone who is highly allergic to cats I hope never to have to share a plane with one.
There are also a lot of people who are allergic to dogs but dogs are allowed onto trains, buses, cabs, Uber and just about everywhere else. When some restaurant is accused of having trace elements of peanuts in food and someone has an allergic reaction to it then there is a massive outcry and reprecssions but when the same happens with dog hair then it is considered just a normal part of life.
As a side question, has anyone ever seen any dogs, including guide dogs, on any planes that belong to Gulf kingdoms or even Malaysia, Brunei or Indonesia? Dogs are considered 'filthy' animals in these parts of the world.