Because users don’t want to be fooled twice.
It happened only once. Exactly once, but it was more than enough. I had written a way too long comment on someones blog post. A Blogger blog, if I recall correctly. Because it had Google’s comment form and, you know, that standard Blogger layout. And that bright-blue “Publish” button I used to submit the essay. And then the comments again. Without mine. And not a warning or error in sight.
Had it not eaten my comment that one faithful day, I might not have been counter-conditioned into pointless user behavior. You see, that event left me so traumatized, I instantly developed the irrational fear of it happening again. Now whenever I’m about to publish a comment, religiously, I select all and copy, just in case my texts find themselves banished to the shadow realm.
Never again, I mutter, and mutter again.