I can see an argument for pretentious being made because of the out of sequence structure of the show. It can be argued that they don't have a compelling story to tell sequentially, so they have to tell it out of order to make it seem more complex and mind blowing than what it really is. That in addition to having the show rely so heavily on mysteries and fan theories to generate the buzz and interest, with many of them boiling down to the same trick of revealing that a character is not what we think they are, or not dead when we presumed they were dead.
Carefully withholding information (or if I'm being uncharitable, convoluted out of sequence storytelling devices), high production values, excellent acting, and contemplative monologues can distract people for awhile in thinking that the show has something reaaaaaaally deep to say, when actually, what they have to say is more style than substance. Teasing the audience with more questions than answers can work for awhile, but it's only so long fake deep shows can pretend.
I'm actually not ready to commit to that argument because I like a lot of what the show has done. I like the questions they ask and generally enjoy the dialogue (depending on the character). I'm still waiting for more pieces to come together before I decide if the storytelling devices are worth it but I can see how some could have already decided after 1 and a half seasons that the beats and repetition they employ to tell this otherwise simple story make the show pretentious.
Especially when the intelligent aspects of the show are marred by some really stupid writing decisions and plot holes. The Delos security team and the scientists working at the parks seem like incompetent imbeciles most of the time, so half of the time I'm asking if I missed something or if this smart show is just so smart then I should give it the benefit of the doubt in ignoring when something seems stupid. I can see how others skip that and immediately say the show is dumb and not as smart as it presents itself to be.