I don't know if you're immature or not. I know that the view that "all creative work is fair game" attitude is not one based on anything but your opinion. I have explained it to you, both yesterday and today (it was definitely you as I confirmed it). I have shown here where creative works are creative works and are all the same. You cannot just declare them not to be. I've shown the factual definition of plagiarism. You cannot just declare it not to apply.
Yes, sharing ideas is good. I post an original idea, you like it, you should share it. You should not, however, take my idea, repackage it, and then post it as your own under the pretense of "sharing" or "reposting".
The facts support my side... creative works are protected by copyright the moment they are created. There are not legal exceptions for memes. Again, while the law supports me, it's nothing to go to court over, I'm not saying that.
However, fostering an attitude of "stealing other people's creative works" (yes stealing, it is what it is) is not beneficial to the site or the people using it.
Share away. Just don't steal.