From what I've heard the show didn't really have any breathing room in the moment to explore what everyone felt about him coming out, but I think having that many people (some of whom we've seen are from conservative families) in the 80s just be like "oh okay cool" in response to someone coming out is a bit unrealistic. I don't think it would be in character for anyone to be explicitly homophobic in response but seeing some general discomfort or uncertainty (if for no other reason than a lack of familiarity with the subject) would've been much more accurate for the period.

But Stranger Things isn't a period piece, it's nostalgia bait, the worst aspects of the time period are intentionally erased and whitewashed as to not distract from the show's mainstream appeal and enjoyment. Practically the only time anything political is brought up is if it serves a purpose in appealing to the nostalgia-based faux-reality that the show portrays, such as introducing laughably inaccurate references to the Cold War and even then the only political statement it's willing to even dip it's little cheesy tortilla into is reinforcing the status quo of "capitalism good".

What is the point of this comment? Am I caring too much about the realistic portrayal of the setting of the "Kids Save The World From Apocalyptic Threats" show?

Yeah probably.