I am sure the authors and signers of the reactive manifesto are well-meaning people, but the entire tone and concept of the site is just wrong.
On a technical level, though, the reactive manifesto is too vague to critique. I could try to interpret and respond to some of the vague claims that seem wrong or silly (for instance, I detect some confusion between an asynchronous API and an asynchronous implementation), but then I fully expect defenders to define away the criticism or say I've misinterpreted things. Its arguments hold up only by being not even wrong.
When you cut through the bullshit, it seems the only actual information content are inane or tautological statements like "being resillient to failure is good" and "one shouldn't waste OS threads by blocking". Do we really need a manifesto to tell us these things? Of course not.
But the point of the reactive manifesto is not to make precise technical claims. Technical arguments don't need manifestos or rallying cries. Imagine the ridiculousness of creating
quicksortmanifesto.org to rally people around
O(n*log n) sorting algorithms as opposed to
No, the reactive manifesto is a piece of pop culture, which I mean in the sense used by Alan Kay:
Computing spread out much, much faster than educating unsophisticated people can happen. In the last 25 years or so, we actually got something like a pop culture, similar to what happened when television came on the scene and some of its inventors thought it would be a way of getting Shakespeare to the masses. But they forgot that you have to be more sophisticated and have more perspective to understand Shakespeare. What television was able to do was to capture people as they were. So I think the lack of a real computer science today, and the lack of real software engineering today, is partly due to this pop culture.
In the reactive manifesto, one is invited to join a movement and rally around a banner of buzzwords and a participatory, communal cloud of vagueness. Well, I don't want to join such a movement, and the pop culture and tribalism of our industry is something I'd like to see go away.
I would welcome some interesting precise claims and arguments (that aren't inane truisms) about how to build robust large systems (there may even be the seeds of some nuggets of truth somewhere in the reactive manifesto). But let's not make it a manifesto, please!
Update: I recently received a note from a recruiter, which contained the following gem:
We checked out your projects on GitHub and we are really impressed with your Scala skills. Interested in solving hard problems? Does designing and building massively scaling, event-driven systems get you excited? Do you believe in the reactive manifesto? Let’s talk.