It's an analogy (if an imperfect one).
I've noticed that to "progressives" it's OK to be prejudiced against those "bible thumping" Christians.
They are considered "slow" and not too bright in certain left-wing circles, don't you know?
In other words "progressives" often think it's OK to single out Christians and will employ various pejoratives against them: in their attempt to denigrate same.
Perhaps you missed it but I thought the sarcasm was obvious.
Hope the above helps.
Have a nice day!
STE=Q
...too close to the edge STE=Q, ....too close