Wikipedia is an encyclopedia. Being as detailed as possible is its goal. Simple English Wikipedia exists for shorter easier to read versions of articles. Generally though, turning a complex topic into a fun easy read is the goal of good scientific journalism, which is also important but a separate effort from an encyclopedia.
Encyclopedias are for summaries, not maximal detail. For that, you look at the source material.
I'm normally against conspiracy theories and BS like this, but...
There's a pretty stark difference between the first few paragraphs of the HIV/AIDS page and the first few paragraphs of the Type 2 Diabetes page.
Both are "factual", but when I read the HIV/AIDS page, I feel like someone is trying to convince me "HIV is not a bad disease".
No, that is not the point of an encyclopedia. The point is to condense an entry as much as possible while being thorough enough to cover most relevant information.