he hates them because they do absolutely nothing and they annoy him alot. Sky's hatred for squids started in the arctic episode where he saw a squid on the ground. he thought it was cool at first until the squid annoyed him. And thus the hatred was born. Squids would later appear in sky's videos and where they annoy him. he usually gives them an annoying "nexed door uncle" voice. And they would constantly say "hey sky, whatcha doin?" in the middle of his commentaries.

Hope this helped!

- Kax