It seems to me that the author is very young, and very concerned about what others think of them. Which, to be fair, is something that often fades with age. I can remember when I was in my 20s, I found eating alone to be uncomfortable.

But as I got older, I realized that I don't care at all what other people think about whether I'm eating alone or not, what I order, how fast I eat, etc etc. As long as no one is harmed, I just do what I want, and if other people don't like it, fuck 'em.

But this perspective comes with age.