Sure, I found some examples in this very comment thread! These show that filtering is effectively not being done. And it's not anecdotes based on single/rare comments.
I've seen that same spam, and I rarely look at youtube comments. Unless I'm extremely lucky to have seen the exact same comments, this is a widespread problem and proves that even trivial filtering is not being used to block rampant spam.
So, more anecdotal evidence. If you really trying to say that your personal experience and experience of few other people proves that even trivial filtering is not being used, my arguments won't change anything, you already know everything, it seems.
The argument that there is a filter set up to block spam can be disproved by a single comment that would have been blocked by such a filter. I'm not sure what kind of evidence would actually sway you, but it seems fine to me: 1. widespread spam exists, 2. a week later it's still happening 3. therefore any filter is not set up in a way that blocks spam.
BTW you did make a claim that Slashdot would give filters to Google so there is that.