Plagiarism isn't limited to writing, it can be anything either an image, a song, a movie, ideas and content in any form or another person work without given credit to the original owner.
Most often, people that engage in this are just lazy to craft their own ideas, they are thief that don't want to work, want things the easiest ways.
These are People trying to become what they're not, especially those that wants to contribute in almost everything, and which they don't have much knowledge about it, they usually end up going to copy other people's work in order to complete their quota here or become relevant here, but when you have something you can offer, I bet you won't be among those that will want to copy or plagiarize, just as I'm a trader, I talk from the point of experience, also I can put up a topic base on experience or what I don't know which I want to learn and not to teach what I don't even know and on the process to try to claim ownership.