Generally, my assumption is that when an otherwise intelligent person advocates for brainwallets, it's because they are hoping that foolish people with weak passphrases will store significant sums of bitcoin that they can later steal.

If you want to personally use a brainwallet. Go ahead.  None of us are stopping you. However, if you are going to advocate for them, then foolish people will read what you write and will lose money.

Anecdotal evidence (such as examples of brain wallets that haven't yet been cracked) aren't proof of anything.  The fact that something hasn't been broken yet is not proof that it can't be broken. I'd think that would be obvious.