Infantilization seems to be a wholly inaccurate description of the behavior; "pandering" or "courting" is much more accurate.

TBH, if folks are having fun, and companies want to join in, I see nothing wrong with it. Devs are likely aware that the companies don't normally wear super hero costumes, and companies are probably aware that making a good first impression is only the first part of a successful relationship.

The blog post seems to have a pretty toxic view of employers (there are a bunch of assumed "to be explored" paragraphs), and I think that view is poisoning the entire experience.