Well, once your network is big enough (hello, Google!), it turns around - given the size of Google's peering network, an attempt to DoS Google's pipes results in your attack bots ISPs being DoS'd, not Google.
Perhaps the perp was a butt-hurt flat-earther, upset by your post of a day or two back. That said, having listened to one or two interviews with flat-earth adherents, I doubt many would be capable, even with (as seems highly probable) the requisite time on their hands.
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