"I do not like tea."
What does the は marker does? it marks the topic right? what's exactly is the topic? is what you are talking about. Some of these sentences are missing the context and are hard to understand why or when to use は and が but it all comes down to topic and objects. Japanese people always use が to mark objects of emotion that are being related to someone or to yourself, this relation often comes with things you like, what you make, what you are choosing from some list, what you want, etc. So in short the が is used to emphasize something, usually an object but can also be used to emphasize a subject. If you see が in a text the word right next to the left of the particle should pop in your head.
let's see some examples...
Someone ask you what beverage do you hate the most and you say お茶が嫌いです (it's tea what I hate), the お茶が part it's like making an emphasis that THIS is what you hate.
You are with someone and you want to give your friend a hint of what you want for your birthday... セーターが欲しい, it's a sweater what you want.
which color do you like between these (while pointing to some sweaters)... 赤いが好きです... It's the red the one I like.
So why would you use は to say that you hate tea?... that's simple, when the topic is not clear. For example:
Your friend ask you if you hate coffee and you answer お茶は嫌いです (I hate tea) ... you are changing the topic and contrasting to the other topic that someone else brought.
You are walking down the street and your friend ask you if you like dogs while he pets a stray dog and you say 猫は好きだ (as for cats, I like them). You are changing the topic, literally.
This can be used to say rude things indirectly, for example your friend ask you if he's good looking and you say 頭はいい (...you are smart) you prefer to change the topic say that he has other good features. If you wanna make it a compliment you use 頭がいい because is like you are choosing between the good features and you are picking that one.
tl;dr: You use が when you are choosing something from a list, when you are liking something or when you are pointing something out. You use は when the topic is not clear or when you wanna make a contrast between an old topic and a new one.
Anyone else annoyed that an adjective 嫌い is translated as a verb 'do not like'? This seems to be a common pattern with JP-EN translations to replace adjective with a verb and vice versa.
I know it sound more natural to say 'I do not like tea' but that's just confuses the hell out of me when it's actually 'Tea is dislikeable'.
Would it be accurate to say that 好きじゃない means "not liked", while 嫌い means "disliked"?
E.g., お茶が好きじゃないです means "I don't actively like tea", while お茶が嫌いです means "I actively dislike tea"? The first might imply "I won't go out of my way to drink tea", and the second "I will go out of my way not to drink tea"?
Sorry if this is unclear.