In two previous questions, it was clearly agreed that hesitating before playing a singleton specifically, and hesitating during play as a bluff generally constitute "wrongful/unethical hesitation." As an advanced beginner, I don't understand this rule at all.

I know that at the highest level, the best way to play and not give away any information about your holding to the opponents is to play each card at a nice even tempo. I am not a world class player; I am not even an advanced player (if I endplay you, I promise it wasn't intentional). As such, I frequently need to pause and calculate what to play, even in situations where the correct play should be obvious. 

Knowing that I will inevitably need to pause and consider a play and that that pause will provide my opponents with the information that I had a potentially difficult decision to make, why is it considered unethical for me to occasionally insert a similar pause before a routine play?

It isn't as if I could use such a pause to reliably signal something to my partner. In fact, this strategy removes the temptation for partner to draw unauthorized inferences from my pauses.