Ya know, I'm not accusing anyone of this, but this current part of the thread/conversation is reminding me of a DM I had in the past in which "magic didn't work" and "tactics didn't work". (This was when we were younger, he's much improved in terms of degree and flexibility now, btw.)
His favorite class was fighter, and he basically viewed D&D as trading hps back and forth. It was a fairly constricted view of the game, and was fine when he played. Well, fine-ish, as he would frequently charge into groups of low level enemies which could have been wiped away by a single fireball, and used up far less party resources than all of the hps he (and others) traded.
As DM, if a player had "Freedom of movement" on him, it was usually more of a "target of hold person deflector" in that he would never target that player with hold person, and would instead pick the next best target. If players fought a group of zombies, the zombies would use intelligent tactics to battle us. I don't mean intelligent in the sense of clever (these he would feel would be cheating...like if the zombies forced a bottleneck, or attacked from two sides or coordinated with a trap). I mean that zombies would all attack the same pc, selecting the least armored one and surrounding it, all the while ignoring all other pcs (basically using knowledge and working as a coordinated group despite being mindless).
To him, using tactics was "cheating the game" and he'd even call basic tactics (such as the ones described in this thread) "metagaming". GOD HELP YOU if you used magic in a creative way (like trying to bring down a cavern with soften earth and stone on the ceiling instead of the common use of the floor)..it simply would never work.
My point here is that he's an extreme example of how some DMs view the game and their own DMing style. He still has a flavor of his prior behavior, and sometimes has to be reminded (e.g. Why isn't the guy targeting me with hold person?..."oh yeah, right....he targets you and it fizzles).
Sometimes DMs feel as though awarding players "easy" wins with minimal loss of resources is bad dming or player cheating, even if done well within the constraints of the game (and even within the constraints of what the characters would know...without any metagaming occuring). If a "hard" combat isn't "hard" there must be some shennanigans, right? My example DM still has a bit of this attitude, and has to remind himself that when players win through in game tactics, it's not an "easy win" because they're cheating...it's an easy win because they're playing well.
If it rankles some that playing well results in less need for healing because of less hp loss, I wonder if some of this is from a perspective on how the game is "supposed" to work, as with my DM example? Like I said, I'm not accusing anyone of this. I don't even think it's something one can be "accused" of. It seems like merely a different perspective on what people want to get out of the game, and what they think is central to the game.
(BTW, lest people think I'm ragging on him too much, the person I mention still DMs for me, I enjoy his campaigns, he plays in mine, and he's a lot of fun. I merely mean to bring up his style and attitude as one that is somewhat central to his understanding of how he thinks the game works/wants the game to work.)