Let me put it this way: the fact that it's "not VERY controlled" and the participants are at home is even more reason why Kelly Whelan should not have made that letter public. The participants can easily find and read that letter while they are still participating, before they learn which arm they were in.
Think of it this way: if a participant wrote a NEGATIVE letter saying something like "It didn't work for me at all, it had no effect, it's junk," Ilfeld wouldn't want the other participants to read THAT during the trial, right? It could influence their expectations and responses.
The same is true for a POSITIVE letter like the one Whelan made public. From a purely scientific standpoint, Ilfeld doesn't want them to read that either.
How ethical is Ilfeld, weighed against how much he wants to conduct more studies? Will he mention Whelan's gaff in his analysis? Or will he keep quiet and hope the grant reviewers don't find out? Because it really does matter, to scientists anyway.
Whelan obviously didn't ask Ilfeld for permission to make that letter public. She saw an opportunity to self-promote and either didn't understand the science of keeping that letter private or just didn't care. Either way, it's a perfect example of why she's unfit to be a CEO of a publicly traded biotech.