You’re reading more into it that is stated.
If you don’t mean to be hostile or oppositional, you should be aware that you are choosing very hostile words.
“I don’t need it” is not hostile.
“It goes straight in the trash” is hostile; it implies that it can be of no use to anyone. You’re obviously speaking metaphorically, but to extend that metaphor, throwing it in the trash would be how one disposes of something, so that no-one can use it.
Also, “I don’t give a rip” means it’s not worth a fart. That’s mildly vulgar, but very demeaning of someone else’s work. Again, hostile.
The more you debate that you intended no such hostility, the more you should pay attention when you are informed that you have chosen hostile words.