It does not seem like an attack to me, rather informing readers of possible blindspots or conscious/unconscious bias in the author's point of view. I think it's only human nature to cheerlead something that one has put a significant amount of effort into making. I, as someone who does not know Swift and who its author is, would be more inclined to seek out alternate points of view after knowing that the author of this article is also the author of Swift.
Just as one would take any marketing/promotional material for why a company's products are better than competitors with a grain of salt, and would want such material to be clearly marked as marketing material, I think bringing to light the author's relationship to the Swift helps, and does not hinder, further discussion.
If presented in the context of a substantive comment about the assertions, I'd agree with you. Without any such substantive comments it's simply assuming the worst about others. The HN guidelines [0] are actually pretty darn good guidance for encouraging intelligent discussion of complex topics, and by my read advocate for more thoughtful approaches to commenting on multiple fronts here, including not posting shallow dismissals or assumptions about astroturfing and shillage. Again, if there is a concrete objection to the logic the author took time to detail in their post, by all means that's a great topic for discussion, and that's where we would all actually learn something positive instead of just insinuating something negative.
Just as one would take any marketing/promotional material for why a company's products are better than competitors with a grain of salt, and would want such material to be clearly marked as marketing material, I think bringing to light the author's relationship to the Swift helps, and does not hinder, further discussion.