But I am viewing it objectively, and just judging it for what it is, rather than giving it a free pass for being an old show. I watched this before DS9, and after Voyager (and I have no interest in BG), but I'm judging it as a self contained entity, and the plots of many individual episodes are just ridiculous. There's just no way I can take American Constitution planet or Nazi planet seriously.
By an objective comparison, the show largely looks very silly these days imo. There are some episodes that are genuinely great Trek (and it's undeniably classic scifi), but I seriously laugh my ass off through about 90% of the episodes.
That's my point. If I judge The Good, the Bad and the Ugly or The Big Country based on modern standards I'd find them equally laughable. Public hangings? Complete lack of public order? Thankfully I don't and consider them exceptional films.
Also, all of the other series have equally stupid plots. Were the dinosaur or Janeway/Paris lizard humping episodes really any worse than The Omega Glory? (The Nazi episode actually had a perfectly decent explanation, so I won't count that one).
Sure, the other series undoubtedly had some equally terrible episodes, but they were the exception, not the rule as they were in TOS. There are only a handle of TOS episodes I can watch without genuinely laughing out loud.
I don't know what you class judging it objectively as, but that shouldn't involve watching it through the eyes of a 1960's kid. It should involve judging it based on logic and believability, and by my judgement, the plots of TOS don't hold up the vast majority of the time.
I can watch films from the 1930s by the same objective judgement, and love them, so it's not about judging them by unrealistic modern expectations. I'll gladly overlook the tacky sets and technicolour lighting, I just want a basic plot that holds up without shutting my brain off entirely. I love Voyager, so I don't think my standards are all too high here.