Funny thing is, I don't even think it's that strong. I mean, yeah, I can see the possibilities, but you're grinding your deck - which I always hated doing, even if I was playing a recursion deck - just for a basic, which, in Commander, is drowning in nonbasic.
Ah, you've never seen it. These decks don't run any basics at all, so there's no "grinding your deck for a basic." The default path to victory is to activate Hermit Druid with one other creature on the board, mill the whole library, take Narcomoeba's trigger, sac all three creatures to flashback Dread Return on Angel of Glory's Rise, then tap a human wizard using the ability of Azami, Lady of Scrolls, which will then trigger Laboratory Maniac's win condition. But it has a lot of other options to back that up. Barring disruption, which isn't normally prevalent in casual Commander games, these decks are quite fast, generally winning on turn 3 or 4. But they can also be very resilient against disruption, recovering from having a spell countered to tutor up something that still allows for a win just one turn later. In "competitive" Commander duels, this is pretty strong, but unless everyone else is a broken deck to the table or multiple players are running highly disruptive decks, it likely isn't enough to stop Hermit Druid anyway. There are other ridiculous Commander decks that I've seen built for sheer brokenness, like hybrid ramp/combo strategies, but many of the other broken archetypes also run five-color commanders just to optimize their access to the best bombs in every color, rarely bothering to actually cast their commanders or use them in any way. I've seen elf-based decks run Karona for her tribal boost. Hermit Druid decks were usually running some commander that gave a hint of a nonexistent theme as a means of tricking people into believing that they were innocuous decks.
If EVERY 5-color runs Hermit, then consider me against the grain. For my personal preference, I'd NEVER run it.
Hermit Druid is just the one the most prevalent one I've seen. It's pretty easy to break Commander if you don't care about being sporting about it. Elf-combo, storm, and five-color broken stuff in general can pull off the same sort of thing. One could probably make a totally obnoxious combo deck that is monoblue or monoblack, but there's not much one can do about that. It's easiest to go broken by just using all five colors.
I don't think you're going against the grain. I suspect that the vast majority of the people using five-color commanders are trying to do so legitimately. My "kill all five-color Commander decks immediately" stance misses that point and ignores the fact that three-color decks (or even two or one-color decks) could still go broken. So why still do it? Well, that gets a bit more complicated. I'll eventually address these issues in an article, but for now...
The real problem here is that in Commander, the rules council stopped banning cards for power level under the rationale that the banned list would become incredibly long. The idea is that everyone who is using Hermit Druid to win games on turn 3 is doing so on purpose, and that this is a casual format and people should just not be jerks, so that card doesn't get banned, but that somehow people will think that a bad card like Biorythm is fun and will play it and accidentally make it work and make it play in a manner that isn't fun, so that card
does get banned. Because of this, the list of actually degenerate cards that are banned in the format is really quite short. Even many of the cards that were ostensibly banned for their power rather than because of "fun" are actually less egregious than cards that the format allows. The format also has the inherent color-based deckbuilding restriction, so the only way to have access to a pool of cards with more than three of the five color symbols on them is to play a five-color commander. It doesn't matter
which five-color commander if you're just going to win the game on turn 4 anyway. But for most people, Commander really is a casual format and they don't have an interest in doing this. I get it. And with just that, it would be silly to go after the innocuous majority of five-color people just because of the broken minority. Say, remember this thing?
It's fine if you don't. The card had Extended decks based around its capacity to power infinite combos, and some of those were successful in big tournaments, but this was about thirteen years ago. Aluren has also had a very slight presence in Legacy, primarily being noteworthy in that format for its use of ridiculously rare and expensive cards rather than for its negligible tournament presence. I haven't seen anyone try to use Aluren in real life in over a decade, and even back then, it was somewhat obscure. The vast majority of people playing Magic today were not around to witness the old Aluren decks. If I go into a multiplayer game now and find one of my opponents using Aluren, it's quite possible, especially if this is a younger player, that my opponent doesn't know about Aluren's former tenure as an infinite combo engine, and is just using the card because it looks cool or something (Aluren is an obscure $5 rare, so it's not too difficult to pick some up). But even if most people do not remember Aluren as an infinite combo deck (either because they weren't around back then or because it didn't make an impression), I do remember it. So if I see it in a casual multiplayer game now, I'm going to do what I can to stop it. Maybe I'll be the only person in the room who even knows that Aluren was used in this way. This might make my inordinate focus on one opponent baffling to the other players, but I'm fine with that. Five-color commanders are sort of like Aluren in this respect. Yeah, most people might not know about the most broken application, but I'm going to err on the side of murder anyway.