I too feel, from what I have seen, that the writing is a bit odd when it comes to the parasites. I have just played a little of EA and that was when it first came out. I do follow the game closely after the last PFH. For instance I have no personal experience with "Daisy".

Pretend that you are one of the people new to BG3. You recently saw a movie with DnD in the title and now social media has exploded over a bear. You decide to give BG3 a look and like what you see.

In the game:
You get a parasite in your head. Eeek, get it out.....
Your party is pushing for getting rid of it ASAP and pretty sure you would want the same thing.
Consequence, (pushed to its point): Skip long rests where the companion stories progress and rush the main story and don't stop to smell the roses on the way (so skip all side content).

Then suddenly your guardian show up. By "definition" a guardian is someone that looks out for your well being. This guardian wants you to embrace the slimy little worms.

WTF!!!! (in the voice of this new player) How am I supposed to handle this. The narrative is pulling me in different directions all the time.

Granted this is based on not nearly enough information but again from what I have seen so far I have no clue how I'm supposed to react in game.
While this might be ok in some ways. You do not want to know the ending of the book before you read it. It is complicated from the point of view that this is a game where you have agency to influence things. By at least my definition that means that when I make a choice I expect some sort of result that I can relate to that decision.

I'm a tad worried from what have seen here that I might get some really nasty surprises that I did not at all expect (as I might interprete what the game tells me differently than was intended). If I was reading a book where that happens I might well put it aside and it would end up one that I DNF.

I'm a glass is half empty kind of person and hopefully the gaps in what I know will fill in the blanks in a way that makes it all "make sense" once I get to experience the full story in game.