He makes three actionable suggestions, two of which are so obtuse he must be trolling.
Voluntarily choosing not to work for the NSA is great, if your political conscience won't allow it.
Expelling people from established disciplinary societies on the basis of your political conscience will only empower the expelled to take the apolitical with them to new societies. (Which will probably snag some pretty sweet startup money from the NSA.)
Refusing junior faculty permission to accept government-funded work grants that your political conscience couldn't bear would come across as such a flagrant assault on academic freedom that you'd have the last of the radical Marxists left in the English Department raising hell, to say nothing of everyone else.
It's easy to ask other mathematicians to quit their jobs; it's difficult to rein in your own government. It's easy to fume that the TSA employee checking the list for $12/hr should quit her job in protest; it's difficult to boycott air travel in protest. It's easy to criticize the mostly black players on the LA Clippers for what you regard as an underwhelming protest against the racism directed against them (to take another bit of internet culture from today); it's hard to give up the playoffs. It's easy to fume about the NCAA and hard not to fill out those brackets.
It's nice that this guy has a conscience. It's good that he feels empowered to speak his mind. It's fine that he wants to convince others. It's depressing that his very next thought is to how he can skip the "convincing" part and go straight to canceling grants, voiding memberships, and engineering it so that it is "socially unacceptable" in his profession to do otherwise.