I just think this for a while. I don't think we have such an expression which can be used in modern conversation and express the exact thing "salty" means.
But I really got one which is "恼恨", it's quite formal. "恼" means angry, "恨" means hateful, these united suggest the anger because of a hateful thing, and this hateful thing may be a defeat or a disappointment or other something.
But it's really farfetched to call the feeling in your examples as "Hate". Although you can use "恼恨" to express your resentful, but the listener will think "Oh, this one is really fussy."
In your particular usage, I think "可恶" or "可恨" is a precise one. Formally both of them mean hateful, but in oral or on the internet it means annoying and suggests a kind of anger.
You can only use "可恶/ 可恨" when stating things happened on yourself:
D**m, I waited such a long time and got nothing, they've sold out. (I don't know how native speaker say things like this)
If you want to describe things happened on others, you must choose the biggest part of your emotion to show your attitude about his experience:
他去排了半天队结果卖完了, 可气死他了/ 他可伤心了/ 他都服了.
He waited so long and bought nothing because they've sold out, that makes he angry/ sad/ can't believe it. (also don't know if you really say this)
But "恼恨" can be used in both way, just make others feel a little bit werid:
He feels salty because He'd waited such a long time and got nothing for they sold out. (still not sure)
I feel salty because I've waited such a long time and got nothing for they sold out. (still not sure)