A lot of it is disingenuous-seeming PR and hype-backlash. Initially I think it was because they missed the release date they gave for the backer alpha/beta/whatever launch by like, 9 months or something, and delivered a very incomplete product compared to what was advertised.
Personally, I don't like their direction of development and their aesthetic. Like, the initial Starbound playable release was EXTREMELY bare-bones and very much like Terrereraarara in content; it seemed like most of the work had gone into a random-generation dealy that made monsters look different, but they still all play relatively the same. Very little of that work paid for the player. Development has continued to be really slow, and the Starbound team keep doing things I don't like, like the linear tiers of materials (and gear-crafting mostly requiring you to combine the previous tier of gear with new materials, rather than just letting you make the thing out of the new ore itself).
On the aesthetic side... man, it just feels like they're really wasting their opportunities with their scifi setting. You start with like an old sword or something, not a gun or a knife or a fireaxe or a crowbar - it's the future, why do you have a sword? I get that a lot of fiction has space marines using close combat weapons to minimize collateral damage and as an adaptation for ship corridor combat, but that's never mentioned. Furthermore, there is a massive variety of melee weapons, but not very many guns, all of which come in later tiers (and as far as I know are not available before killing your first boss, which is a penguin-spaceship. Which you fight with no guns. As in, you shoot arrows at it until it falls out of the sky?). You quickly pass up your fancy scifi 'matter manipulator' for a buncha primitively-crafted pickaxes, which are vastly superior to your spacetech shit. Why not just craft upgrades to the matter manipulator? Power capacitors, material structure data, projectors, fuckin' whatever, just make it seem spacey. Last that I played, there isn't really any gear that you can equip beyond some armor... no room for air filters, jetpacks, air or fuel tanks, shield generators. Every planet has nice, breathable air and a mostly non-hostile environment - no atmosphereless planets, low-magnetosphere-protection planets, no sun-blasted planets, no poison-atmosphere planets, none of that shit. Mechs and vehicles are a weird kinda power or something, I guess? There's even a fucking magic staff. Ostensibly it's a tesla rod or something. But aesthetically, it just reminds me that Starbound is Ttererararrrara except pretending to be in space.
And like, I know it's just a game? But the atmosphere is just fucking inconsistent and weird. Like I said, the first boss is a spaceship piloted by a contingent of penguins. There's a literal shit biome, where you're tunneling through excrement. What is this I don't even.
It's just... alright, there's this fuckin' scifi porn game, right? In this game, you go down to the center of a planet, and you end up having no gravity, because you're in the middle of the planet so all the planet's mass is gravity-ing you from all around equally, instead of just from underneath. That was some cool-ass scifi-feeling shit. From a porn game. I got that 'scifi' kinda feeling more from that dumb porn game than I ever got from Starbound.