I am sorry you had to deal with a troll so soon after having just returned to writing, Leonard. I don’t think I have experienced a troll commenter on Medium yet, but I have experienced them elsewhere.

What I do is turn their derogatory comment into a joke and reply to it accordingly. Possibly with a laughing emoji.

In my experience trolls want you to be upset, so being laughed at is the last thing that they expect. They hate it in fact, and will usually slink away back into their mother’s basement.