Remina seems to plow through most planets, devouring them at a rapid pace. It made a beeline for Earth upon spotting it, and actually takes time to savor our planet before eating it. It's very possible that planets capable of sustaining life, with all the lovely water, vegetation, and... well, meat, taste much better than others.
The story of Remina's torturous pursuit seems to be an analogy for celebrity fame. At first, she resists the attentions of the public, but soon she has fans doting for her and crowds obsessing. Her corporate sponsors scrabble to impress her, until finally, events beyond her control make the attentions turn negative. The crowds become mobs, the fans become psychopaths and fickle allies, and her clothing becomes less and less, symbolizing impurity. It is only when she settles down to a mundane like of anonymity that the Hellstar spits her out. The eye of the world no longer gaining scopophilia.
Think about the sheer scale of Planet Remina compared to the Earth. Now think of the size of Remina compared to a human. Now think about your own size compared to that of a single-celled organism (bacteria). Now think about all those organisms on the food you eat every day. Do you have any understanding of what goes on with your food, on a cellular level? Every bite you take destroys billions of tiny single-celled lives, but you don't give it even a cursory thought... Just like with Planet Remina. As far as the monster was concerned, Earth was just especially tasty food. It may not have even realized that the humans were even there.
Though from the fate of the astronauts, it seems that it's aware of the people on the "food" its eating.
Many other planets inhabited by possible future alien civilizations will suffer the same fate as Earth, assuming they don't have advanced enough technology to save themselves.
As if it wasn't terrifying enough, the man whose helmet was taken off almost appeared to have been absorbed into the planet's surface, transforming into another blob of eyes and tongues. What if he's still sentient?
Which also begs the question, are all the other eyes and mouths and tentacles on the planet made from absorbed people or aliens? And after Earth is eaten, did everyone else living there become huge masses of tongues and eyes?