Technical explanation: the problem with MWI is that it makes the fact that density matrices work seem like a complete epistemological coincidence.
Incidentally, I remember a debate between Eliezer and Scott Aaronson where the former confessed he stopped reading his QM textbook right before the chapter on density matrices.
I don't understand what you mean. Could you explain? I'm familiar with QM, so you don't need to avoid technicality in your explanation.
As per a recent comment this thread is meant to voice contrarian opinions, that is anything this community tends not to agree with. Thus I ask you to post your contrarian views and upvote anything you do not agree with based on personal beliefs. Spam and trolling still needs to be downvoted.