This dosen't seem overwhelmingly likley false.

It does to me. Less Wrong isn't so popular that I'd expect a herd of people to bother downvoting each of Vladimir_M's dozens of posts, then wait around for him to make more posts to downvote, just because of a few examples. The fact that Vladimir_M gave two or three examples but still has non-negative scores for his recent comments is more evidence that sam0345 was wrong.

Its not a very nice things to say, but why should that matter?

Quite a few LW users see niceness as a useful norm and may have voted accordingly. At any rate, I don't think it was a lack of niceness that provoked people to downvote that comment; I'd guess it was because they read it as an unhelpful overstatement.