Originally Posted by Faterson
To me, it would be. You seem to have only about 6-7 words per typical line of text, whereas I have around 9-10 of them (2013 Nexus 7). That indicates either that your screen is smaller than usual on tablets, or that your font is larger than usual on tablets. And that's OK, but you then need to accept some of the consequences this brings in the display of e-books.
I heard a recommendation that for text to be nicely readable, lines of text should contain approximately 60 characters -- not more, and not much less. I think my preferred themes in Moon+ Pro contain between 40-50 characters per line of text, so I'm pretty close to that recommended ideal. In your screenshots, you have -- a rough guess -- only about 30 characters or so per line of text, which again indicates a rather non-standard setup for a tablet screen. (One would be more likely to expect to see such short lines of text on a small mobile-phone screen.)
I have a Nexus 7 too. You should see how few words per line on my phone! I used to prefer full justify for my books but with a font size small enough that it was formatted ok it was just too small to read. My vision would be double after reading from the strain. So I did have to get used to the left justify, but it's better than double vision.