The entire psychology of the article is obvious. Throughout history, any attempt to address social inequality of any sort is met with strong backlash. Those used to lots of power are not likely to give it up easily. What was once a luxury becomes a necessity. As feminism, civil rights, and gay rights became more mainstream they faced similar problems. Sexism, racism, and homophobia became more vocal — most recently by the backlash against Maryland's allowing of same-sex marriage. It's clear that Mr. Ehrlich feels personally threatened by Occupy's presence.
This letter won't stop him nor other people from attempting to discredit the movement. The same arguments will be trotted out, attacking perhaps the fact that the movement's goals at this point are abstract rather than concrete, framing the movement by the most extreme parts of the group, or claiming that their goals are anti-American. These tactics are meant to push hot buttons rather than provide for any logical discussion. However, those attempts unwittingly vindicate Occupy's cause. Such responses betray a simple notion, that those in power feel threatened and they will attempt to hold on at all costs.