This reasoning annoys me for two reasons. First of all, it plays into the whole internet mentality that only one opinion about a film can be correct and that other opinions should be discounted or cowed into submission. We've seen this sentiment play out on numerous occasions in the past.
Secondly, it implicitly demands that this film, The Muppets, be less than excellent. Not every film can be an amazing work of art, but is it wrong to expect each one to at least be an exemplar of its category? I think not. Jason Segel (who co-wrote The Muppets screenplay) was handed a remarkable opportunity and substantial resources to work with a beloved property. I found the film to be delightful, a lightly polished piece of light, fluffy entertainment. But as a film, was it emotionally resonant? Did it evince quality, thoughtful storytelling? Did it pay homage to the muppets while bringing their sensibility into a new era? In my opinion, it did not (you can listen to my review for more details on this).
Other people have made this point far better than me. As always, I encourage you to check out the Extra Hot Great podcast's review, which adeptly strips away the nostalgia and evaluates this film with brutal honesty.
I'd strongly recommend Elizabeth Stevens' sprawling essay on the muppets, which is a loving exploration to the work of Henson. In one portion of the essay, Stevens questions why Kermit (once voiced by Jim Henson but now voiced by Steven Whitmire) needed to continue existing at all after Henson's death:
It would’ve made more artistic sense than what happened. Instead of an organic personnel shift, Whitmire became Kermit, which wasn't only a disservice to that character, but also a real disservice to Whitmire. There was no place for him to take the role. If he strays too far from Henson, embodying Kermit with the parts of his personality that weren’t in Henson, nostalgic fans will be disappointed. He can only attempt the same impression over and over. It’s not the kind of art Henson produced. It’s very un-Muppet.
I was reading Matt Gemmell's great essay the other day about why copying occurs so frequently in the tech industry and I couldn't help but think of Stevens remarks. One thing that both writers agree on: a copy can never be better than the original. By consigning Whitmire to imitating Kermit, it's a lose/lose for both Whitemire and for the character.
Stevens' essay was written before the film came out, but if she were to review the film, my guess is it would read a lot like Jason Bellamy's review of the film at Indiewire:
Make no mistake, watching the gang perform “Rainbow Connection” is lump-in-the-throat touching and realistic, too (not that the Muppets have ever been about realism), but it comes off like a concession – that the Muppets’ best days are behind them and the most magic we can hope for is an occasional performance of their greatest hits. Maybe that’s true. Maybe what Segel’s film shows us is that Henson and Frank Oz, the puppeteers extraordinaire who through their voices and hands gave so many of these characters their spirit, are irreplaceable.
Compare The Muppets to a film such as Abrams' Star Trek, which does honor to the original characters while striking out on its own (quite literally, using a brand new timeline). Despite that film's shortcomings, I truly believe it set the standard for how these film remake/adaptations should be done. I'll take Big-Hands-Kirk over endless, empty waves of nostalgia any day. At least the former is trying something new.