OK - let's break this down. It isn't about whether dads with young babies can travel, or how people with FF babies are treated. It's about the absolute basic principle of discrimination.
- Women who lactate can't conveniently 'switch off' the milk supply or simply throw it away. It is a biological fact that they will lactate and that they will need to be able to travel with milk.
- there are certain 'protected characteristics' within law which it is illegal to discriminate against. Charging extra for providing a service counts as discrimination.
so - a service provider (let's not confuse people, we'll stick to airlines) can't charge someone using a wheelchair for causing extra work and taking extra time going through security. They can't charge extra if a person needs a longer lap belt if they're pregnant. they can't charge extra for allowing people with mobility problems to board ahead of others. It's against the law.
- Anyone who has a protected characteristic is legally protected from this kind of discrimination. They are legally entitled to access services with reasonable accommodations being made for them. For a service provider, such as an airline, not to do this is breaking the law.
TBH - a petition shouldn't be needed. Anyone should be able to contact the relevant govt. departments and say 'this co. is breaking discrimination law. Please stop them'.
Airlines cannot charge someone for a reasonable accommodation under discrimination legislation. They're breaking the law. Anyone who wants to try and say it isn't 'reasonable' for a lactating woman to want to be able to carry milk on a flight would have to prove that it was so truly inconvenient that it affects the business's ability to operate, or that women could somehow 'choose' when to lactate or not. The onus, btw, is on the service provider to prove that they're being asked to do something unreasonable, not on the person to prove that it IS reasonable.
(There are, of course, countries where there aren't discrimination laws, but the OP had specified areas of travel)