I don't think anyone is saying David chuckles in the sight of recent outages. The email which was sent does not seem to be a personal attack on David's character and - apart from some random comments - nobody seems to speak bad of David himself.

I'm a Tumblr user and will keep using it for the very reason that the service is simply growing too fast for them to keep up at the moment, but in the end I believe it will stabilize.

That being said, a response like that is just utter crap. (Sidenote: so far, I have seen a copy/paste of the entire message (?) that was supposably sent to Tumblr, but only excerpts of the reply that was received)

Replying in a normal manner to someone that sends a normal e-mail is not something that is left to be done for PR teams and customer service departments.

It really is not that hard. We all say stuff that comes out wrong and there is no need to blow it out of proportion. Seeing that is has already done that, it would probably be a good display of character to set things straight, even if there seems to be nothing to gain from it.

As far as the article is concerned: I believe it could have been written a lot better. Catchphrases like "Could David Karp be the downfall of Tumblr?" are inappropriate and belong in gossip-magazines. The number of claims and experiences on which this article is based (or at least, references) is too low to make it believable and the tone of the article ("Tumblr has been ignoring complaints routinely for the past year whilst Karp apparently indulges in the money he gains from funding") does not really stand out as objective to me.