I can't claim to understand 4chan, but it reminds me of 4chan's past reactions to negative press such as the "Ya dun goofed" incident.
For those who didn't notice "Ya dun goofed" here is a brief summary: 4chan trolled a young girl to tears, provoking the rage of her dad, who then called the police. The incident of cyber bullying caused widespread media coverage, and 4chan responded by briefly adding music to /b/, removing porn ads, calling it SFW (with the blue background theme), posting kittens and rainbows, and deleting porn threads. Needless to say /b/ quickly tired of this and returned to their old ways. However, I mentioned it as an example of 4chan's long history of alternating between making themselves look really bad, and then trying to make themselves look good.
I may be that they are running this DDOS on themselves so that they will be seen as innocent victims just like Paypal, Mastercard, etc.