Well, no...it should be due to how a reader's eyes naturally move to follow panels. If an english-speaker is reading something right to left, their brain has to work harder for them to make sense of the flow of panels. It's not natural for a mind trained in a specific written language like english or spanish.
Right now I'm guessing you don't read translated manga that much...
Most of us who read translated manga are very used to this. It's almost automatic for us to read right to left when we see panels like this. People who aren't will just have to either get used to it or not read it. Nothing big.
I own translated manga, and I know that unless the images are flipped it reads right to left. That's fine because that's how it's originally written in japanese. That's how the flow of panels work. I'm used to it, but it's irritating when people who are writing in english do it. There's no excuse for it.
This is written by an artist in the USA, who is a native english-speaker. It is not written in japanese, and should not read right to left. It doesn't matter if you call it "manga", it's not manga because it's not a comic made in japan. It's a comic. Western comics should read left to right.