Blockchain storage and forcing everyone to post in the clear are different problems. As with facebook, as memo gets easier to use, people will forget what they are doing
Adding extra choice is not a problem. if people don't want it they simply won't use it. If they do want it, they'll clog up memo with encrypted content regardless
@imcoddy free.bitcoin.com is enough to get you started. But having some slight work required means is a good thing. At least they've done their first BCH transaction