Far from new, but not arrogant enough for IT
If you are working in a company where the CEO has decided he wants a mac, and you need to satisfy that need with the cheapest, safest kit available, and this CEO is as you say, clueless based on what he knows, then surely that job is to provide him with a mac . Why would he need access to anything? Why would he need access to this companies sensitive data? that is made by other people, not him. He wants to email powerpoints to other people and receive reports, and be told when his meetings are - he needs LDAP access to exactly nothing, so I am not sure how this vunerabilty matters.
No, I don't do IT, I am one of those little people making the important company data that is worth stealing. I have only seen that behaviour in a small company. MD brought in some laptop, we just told him it couldn't connect to the network as it wasn't compatible and set up his hotmail account. Job done.
In my most recent experience of large networks as a user, the policies they were bringing in meant that i had to spend a large amount of my working week working around them to be able to do the job I was paid to do. And I was not in a unique position. If you think that improves security, I may not be the silly one.
I don't need to do the job to know that that is wrong, any more than I need to be a plumber to know that I shouldn't have to take a bucket to the toilet to flush it.