He was actually thanking EV in that post (one of the few to do so) but lying is in your DNA so I'm not surprised you choose to misrepresent everything to suit your agenda when you could have made the point that Arthur has been poor last 2 games WITHOUT resorting to lying.
That's the problem with you. Won't be taken seriously until you get over this compulsion.
Some posters have literally posted an Instagram post or a screenshot from FcBarcelona Instagram profile with a news: EV sacked.
From Barca's players, only 3 players have liked that post, iirc: Riki, Todibo and Arthur.
Now, I don't know whether that post was photoshoped, a fake news or a real thing.
Or whether Arthur has liked it and later removed a like.
But you can check EV's topic and some guys posted that pic back then.
Then, a few days later, majority of players posted pics of EV and said: thank you, mister.
Arthur did the same.
But now, we don't know whether Arthur has really liked the first post.
And whether his post with saying thanks to EV was just a PR, which is the most likely.
Further, remember that Arthur talked about EV when he was at Copa, something like: I can play more freely for Brasil.
So, there are some hints that he wasn't happy with EV.
Also, media said that EV was mad at Arthur for driving a scooter, snowboarding and about a possible STD scandal, partying with Neymar.
So, there is some smoke...
So, a news where he liked the post when EV was sacked doesn't sound that crazy.