First of all, a number of positive reactions so far are from reputable critics. They're not all Disney shills or whatever, and some of the tweets even acknowledge how surprised they are that the movie actually works. Did Disney likely invite mostly Disney-friendly "critics"? Almost assuredly so. But even the credible ones are admitting it's better than they thought it'd be. Again, that doesn't mean there won't be a wave of negative reviews to come, I'm just saying it's not all shills praising the movie.
As for The Little Mermaid comparison, you have to consider the release strategy for each movie as well, with TLM releasing on Memorial Day weekend, up against…
- Guardians of the Galaxy Vol. 3
- Spider-Man: Across the Spider-Verse
- Transformers: Rise of the Beasts
- Pixar's Elemental
… in the weeks just before/after it hit theaters. Granted, not all of those are direct competition, but they're all PG/PG-13/"family" blockbusters and two of them are animated. Never mind all the late June and July competition as well.
Whereas Snow White has virtually no competition, save for Minecraft, for weeks and weeks and weeks, at a time when most family movies are currently over-performing. In other words, even if Snow White only does $50M this weekend, again, outside of Minecraft, it basically has a six-week runway until Thunderbolts*, and a NINE-WEEK runway until the next legit family blockbuster, Lilo & Stitch.
To be clear, as I said before, I think everything about this movie has been exhausting. I think it looks terrible, I think Gal Gadot is a bad actress, and I find Rachel Zegler to be increasingly annoying/entitled.
I'm not rooting for this movie to succeed.
My only point is, if it's is even halfway decent, because of how starved families are for family fare, and given how barren the family movie landscape is until summer, it's likely not going to be the bomb so many clearly want it to be - even if it doesn't have a massive opening weekend - and that it could, in fact, end up be a decent-sized hit.