I'll address the major concerns in bulk.
1. This isn't plagiarism because tons of people have done it before.
Shoot someone. Rob a store. I think you'll find that the law doesn't really care if someone else did it first and didn't get punished.
2. Nothing is new so every idea is unoriginal so it's not plagiarism
Write a book about a child wizard going to a wizarding school. Make a movie about a teenager thrust into a rebellion to stop an evil mystical empire. See if you get contacted by any lawyers.
Most everything is a twist on major themes. As mentioned, a picture of an atom is just that. There are lots of pictures of what people conceive of atoms to look like. However there are certain combinations of elements that are unique to the creators who popularized them.
Cute killer bunnies begin and end with Monty Python. No one put those particular things together in that particular way (cute bunny curiously surrounded by piles of bones) before they did. The same way you can't start writing books or making shirts about little people with magic rings, you can't recreate someone else's specific ideas lawfully.
3. You just hate ramy because he's popular and are jealous
Find me another popular artist here that I hate. I love tgentry, cmdixon, drakxxx, kasey, rglee just to name a few. I'll give you a hint. They are fabulous designers with integrity and creativity who make original works most of the time and when they make derivative works they make very certain to put their own stamp on it.
ramy gets so much hate because he repeatedly rips off other people without making use of any parody whatsoever. You can like it or not but classic ideas and subject matter are public domain, and Monty Python and the Holy Grail isn't. Their Intellectual Property rights still stand. So to make any derivative work you absolutely have to have adequate parody and there is none here. The rabbit is presented in exactly the same way as the movie with no differences whatsoever. This is just unlicensed merchandise and as with anything else, cashing in on someone else's ideas is plagiarism. It doesn't matter if you think it's better plagiarism than other things you've seen.
The fact is ramy has already done it before. He made a design for the propaganda derby where he shamelessly ripped off Stephen Colbert and his crusade against bears straight down to the "godless killing machines" tag line with absolutely no changes whatsoever.
He has blatantly plagiarized before and will do so again. The bears shirt he pulled himself before it could get rejected because he knew he'd been caught.
He tried to pretend initially the shirt wasn't about bears at all just a generic "thing to be wary of" then changed his tact saying of course he took it from Colbert but it was a tribute and tried to say he googled godless killing machines and found no shirts like it despite the fact that at the time and still now the truthiness wiki and shirts with the tag are the first results.
In the year or so he's been here he's learned to play the victim because new users buy it, but the fact remains he's repeatedly been caught stealing other people's work and some of us are tired of it.