( Sorry this was late yet I wanted this response or reply get to you. Please take your time to read nor you will be able to understand meanwhile at the same time your reading. )
Unless they were re-uploading his original artwork, to their deviations gallery yet they should not be authorized to use MasterBimo's work on their gallery. Yes you are right! From your perspective or view has noticed that someone has been stealing in his work, accordingly to what's mention earlier if they re-uploaded it to their Deviant Gallery, they should not necessarily do that, regardless of the owner who doesn't know about people re uploading or posting the admin's or owner's work.
This applies to YouTube videos that many people faked other channels to be stealing the admin's videos and re-uploading them without their permission or for credit. It does not matter yet they should meet the consequences, unless if the copy cat has copied like for example one of Markiplier's videos and re-uploaded them it's not okay.
I would not forgive them for re uploading them without giving them credit or permission. I remembered it not to long ago so several months ago and realized there was this FNAF3 video funny video, yet there was a user who stole their content, which they created it without giving them credit or their permission.
The admin's was not pleased by it although it's okay that they did it by accident or purpose, however they would not forgive that the user must get their permission instead of giving them credit. Because the difference between given credit and someone's permission are who different topics discussed, in that fact their gonna have to source a link of the original video, yet the consequences still may appear, as situation and encounter which they merely only linked the source to the original video, unfortunately they rushed themselves and think before giving the credit. Then they would have been fine but no. Because the admin's were not happy and left comment on the video which the user was re posting their content for their own views. Isn't that disappointing? It means they didn't ask the admin instead they sourced it themselves without their permission first.
Together if they want to give credit without causing themselves an encounter from the admin or not, then getting their permission, crediting, sourcing from citing it where they will promote to share it. ( They should have favorite and add it to their "Favorites" of their DeviantArt account which should be the proof or reason only if they did follow the rules of given permission, crediting, sourcing and citing the link to their original).
Okay back to the topic about them stealing MasterBimo's work...they should have favorite it in the first place. Probably like for example they look what self taught artists, artists, or illustrator draws, they wanted to draw like them and then become one like them to draw, paint and apparently do larger composition of their work. This means that they like MasteeBimo's work and iil0sey should have not re post or uploaded his work..if she loves it. Why not favorite it?
What do you think?