This is the one problem with BitBucket that makes it hard for me to convince people to buy into it. If people can post anonymous bug reports, and given that initial bug reports are almost always useless until you can solicite more information about the problem, and when they are anonymous that is impossible, anonymous bug reports are fundamentally a bad thing.
That comment was me, in FireFox (not logged into BitBucket) where I was seeing if the problem had been addressed. This is me back in Chrome where I use BitBucket, just putting my name against the comment since I'd inadvertently complained about Anonymous anonymously.
Issue #1932 was marked as a duplicate of this issue.
I agree, this seems like a critical feature.
It would also prevent comment spam like comments 4, 5, and 6 in #3288.
Issue #5560 was marked as a duplicate of this issue.