Is "I love that for you" grammatical?

Solution 1:

Well, the linked Vogue article ("Why Is Everyone Saying 'I Love That for You?'") seems to be a fairly comprehensive history of the phrase's origin, use, and slide into sarcastic shade.

Whether sincere or not, of course it's grammatical English in any dialect. Per the OED, even if you don't think it suits the sense of for as

VII. Of the cause or reason. 21. Because of, on account of: a. a person or persons.

...

c. On account of one's regard for.

it still works for

IX. Of reference. 26. a. As regard, with regard or respect to, concerning...

b. So far as concerns (a person or thing). Used with limiting or restrictive force...

...

27. In proportion to, considering; considering the nature or capacity of; considering what he, she, or it is, or that he, etc. is so and so.

That's the sense that's being used in most of the Vogue examples: I don't necessarily love this myself (indeed, I probably don't much like it) but it's just perfect for you and the kind of person you are. And that's a bog standard application of this particular preposition. (The OED senses are for the most part ordered the age of the examples, not the amount of present-day usage.)