I agree that Hanlon's Razor should be applied here, and yes, this twitterstorm should know its limits (see
http://www.nytimes.com/2015/02/15/magazine/how-one-stupid-tw... and
http://techcrunch.com/2013/03/21/a-dongle-joke-that-spiraled...)
However, I'd like to take you up on two points:
> I'd understand the anger if this were, like, a Goldman Sachs-calibre company practicing age-based discrimination
Are you claiming that small companies should be free to discriminate against protected characteristics with impunity, and that only large companies should be held to account for bad behaviour? Where do you draw the line?
> decidedly not versed in HR laws
As far as I can see, Career Harbour claims to be a revolutionary recruitment company, xiangyu_wu claims to be its founder and CEO.
In order to make those claims, one must have at least a cursory knowledge of the law and customs pertaining to recruitment. "Know the rules well so that you can break them effectively"
Although I can't back this up with quotes now, as the site has disappeared, I think I read that they wanted to "disrupt" recruitment and were targeting the milkround market, by allowing applicants to apply to all the big names with just one form. They may not be a Big Company themselves, but they are pitching themselves as the gateway to them. Were I to apply to PWC or KPMG or whoever through them (with a "magicpitch" video), I wouldn't be surprised to find that they'd not even sent it on, due to the shortage and greyness of my hair and colour of my skin.
Also, (again, I can't back it up, because his own tweets have vanished) it looks like some of the ire comes not just from the awful ad itself, but from his attempt to defend it (e.g. https://twitter.com/digitalmaverick/status/57606722316234752...). That said, in his defence, he has "had a change of heart", which may mean that he is repentant.
Anyway, if, as he wishes his employees to be, he is a "nice dude" who "celebrates failure" and can "accept difficult challenges as opportunity for growth" and "deal with setbacks and failure on a continuous basis", this event will be bread-and-butter for him.