I initially find Buddhism very complex & very hard to understand. I bulk download article & sutta from AccessToInsight and I have re-read all of it 3 times...I still can't 100% understand what it mean..but after time passed I slowly understand what it mean without having to re-read it for the 4th times. I follow Theravada Buddhism the so-called basic & foundation to other strain of Buddhism. I hv to agree with you "Run of the mill person" will have difficulty understand Buddhism.  Understanding Buddhism require "Wisdom" or in layman term require higher IQ & EQ.

But I have read story from Thailand where the people who do not have a strong understanding in Buddhism sometimes can easily go into deep Samadhi during meditation. Understanding Buddhism is not  a pre-requisite to practice meditation and gain insight which is the core of Buddhism. During meditation just follow the monk instruction is enough.

If the Buddhist sect is heretic or the monk is a bad monk, then those who do not have an understanding Buddhism can be easily mislead into making bad deed...this is where sex/financial scandal arise.