I've always had an issue with the Prime Directive concept. Sure, you can see it as not interfering with our development, but the technology and power it takes to travel between the stars could be used to solve many of the energy, material and pollution issues facing humanity.
Unless we are seen as non sentient animals by comparison, it seems preposterously cruel to not help us through the suffering we've got ourselves into.
You are absolutely right about the cruelty. Just philosophically entertaining the "alien" concept, and then entertaining the stories and fears other humans have experienced - putting it all together paints nothing but a cruel picture of whatever "advanced peri/post warp civilization" has visited.
The Prime Directive is supposed to protect both the advanced and civilized races.
If a race of beings, or a planet of beings hasn't gotten to the point where they can come together as planetary residents and work together to help each other, then they don't need outside influence. Racism, classic, sexism, ageism... those things
cannot exist in an interstellar or intergalactic neighborhood. Especially as embraced as hate is today, if we expect to get meaningful, real benevolent and constructive visits from advanced species, we
should be dying holding our breath. Would you try to "help" your neighbor if every night s/he kills and rapes his/her own kind for fun, discriminates against his/her family members, and segregates other members of her species - every single day? No, you may call the police right - and yet, police are humans too. Politicians are humans. Scientists are humans. Parents are humans. Humans kill each other for fun; advanced races seeing how we treat each other on this planet means, if they are wise they would stay away. The ones that would come to "visit" are the secret ones who would exploit the entirety of our planet (including us) for their own gain - and maybe in exchange they will give us humans their technology from 1000s of their technological years ago....
All that will happen in terms of helping humans is the humans purposefully keeping division going for their profit will feign being "honorable leaders," and keep secrets and technology for themselves.
Like is done now: releasing technology for consumer use 50 - 200 years after it has been intriduced (phones, free energy [unreleased], WiFi [Tesla], Internet [1950s military tech], ...)
Aliens can't help us advance if everytime we have a technological leap we use it to blow up a portion of the planet on which we live - all because we let other humans pull our strings. Or, we pollute our resources to maximize profit of the execution of a new technology. If you are immature already as a species, throwing technology as them will only hurt.
If there are intelligent beings, they would know this - which is why IF we have these things existent in our modernity and history, the bad ones or tricky deceptive ones are the main entities we hear about. They are secretive, they aren't trying to help the rest of the world, they are usually rumored to be government bedfellows, and they have a history of abducting humans and animals for (at least) biological and reproductive survey. Then they send those people back into the population - tagged. Those entities aren't the entities I would want to visit my pre-warp civilization.
And, those type of secretive entities are just the type of entities that would try to keep a species from naturally reaching a certain point of advancement - essentially attempting to drive the (non-darwinian meaning of) evolution of the species. They [would] do this with population control (celestial body manipulation, giving a gun to a baby, stupid wars, suppression of knowledge via rewrite and witch hunts, plagues,) and a firm control of technological and biological [darwinian] evolution. That is malevolence.