No, it's a form of discrimination. Most other countries grant privileges to their citizens that foreigners don't get. Australia and New Zealand treat foreigners the same or even better than locals. These two countries are WOKE as f***.
Nope, she's good to go. Only mr. farang has to (interestingly, so do Laotians, which will cause chaos). Malaysia exempts Singaporeans and vice versa for Singapore. Not sure why Thailand isn't exempting it's neighbors. I can see problems for Lao, Burmese and Cambodian citizens who don't understand English and will be forced to fill out this form in English. While border pass holders will be exempt, those traveling on passports will struggle.
In the case of Australia and New Zealand, they should be exempting their own citizens. Other countries do this. Even the USA wasn't requiring arrival forms for their own citizens while foreigners had to fill out the white or green I-94 forms (depending on whether they were coming with or without a visa).
So yes, it's discrimination because Aus/NZ citizens aren't being given any special privileges despite the fact they are citizens and thus should have more rights than foreigners.
In Thailand's case, the arrival form isn't required for Thais, which is the way it should be.