I did not interpret it as promotional. The text of the comments was so non-sequitur that I believed the account to be a straight-up bot account, posting random

I did not interpret it as promotional. The text of the comments was so non-sequitur that I believed the account to be a straight-up bot account, posting random snippets from articles. It was only when I investigated further, when I saw that the same user also submitted all the articles, that I started to doubt my initial impression.