Because teaching someone to play is different from actually playing and setting up scenarios that aren't naturally occurring can foster the learning process.
I feel as if you're being as willfully obtuse as the original poster I replied to so I'll just go ahead and block the both of you. Deuces.

Because it's not cheating, it's a learning tool. It's essentially the same experience as the starter kits that WotC sells that instruct you not to shuffle the decks the first time you play them.
Variables are a detriment to the learning process when you're trying to focus on basic mechanics.

I haven't been in danger of enjoying EDH for a long time. Today's update hasn't changed that. At least my friend who has wanted to build Braids since 2011 can finally put a deck together, but the playgroup hasn't met up for EDH in the last year anyway.