Congratulations on seeing a case where your emotions may mislead you. Now, what makes you think the author of that article "is pretending to be surprised we are not saints"? Looking at it, I get the exact opposite impression - he starts off by saying,

There was something heartening about the indignation expressed by Londoners this week against the “anti-homeless” spikes placed outside a luxury block of flats in Southwark.

suggesting that he finds their reaction surprising. So if anything, his article gives me a sense of self-satisfied cynicism, learnedly explaining to such people how the world works and why he thinks their indignation is rare.

Were I uncharitable, I could read your own (parent) comment as showing off cynicism in the exact same way.