When 'let him be anathema (excommunicated)' is attached to a teaching of a Council, it means that that teaching is part of the deposit of faith, i.e. infallible.
Many Christians in the 16th century had "different points of view from the Church" and became Protestants. 
The same thing is happening today, Catholics are rejecting infallible, irreformable teachings of the Church without realising that in doing so they have become de facto Protestants.
Richard Rohr is hardly an example of Catholic orthodoxy, why he hasn't been disciplined beats me but your quote from him has nothing whatsoever to do with the issue of whether the Mass is a sacrifice or not, nor has your final paragraph.