Something tells me I may regret tossing my hat into this conversation... but here goes...
I wholeheartedly love the alignment system, use it enthusiastically, and recommend it. That said, I am not oblivious to the many emotional opinions around it.
Personally, I think any iteration of D&D should have it. It's like a condom - better to have it and not need it, than need it and not have it.
Those who violently oppose the system can simply ignore it as they do now. A page devoted to it in a game manual isn't going ruin anyone's day. But it's there for those who do use it.
For my own part, the reason I love it is that:
A) As a DM it provides an instant guide to the moral compass of the character(s) in question which guides me in roleplaying. Add to that personality quirks and you have a character ready for instant interaction.
B) It gives my players the same for their characters. As I explain to them, it's not a hard and fast set of rules that they must always honour or be sent straight to the penalty box (with exceptions, see below) - it's a guide to your moral compass. One of several layers that, with other character traits will flesh out the character and let them grow based on the decisions they make through that filter. People are flawed, and as such will say and do things against their morality... this too is good, as it gives players and the DM something to work off of. A character who violates their own moral compass then works to correct it creates scenarios and leads players down fun paths of adventure and character growth.
The exceptions of course, at least for my 1E game being Paladins, Rangers, and Druids who must adhere to their moral compass or potentially lose their status. But that too is a feature, not a bug, as those are the outliers where players know this is the case going in.
Other descriptors are just that, descriptors... but they can be so vague as to not give any notion as to moral compass. Upthread somewhere the term 'bloodthirsty savages' was used in place of Chaotic Evil. Well, I posit to you that 'bloodthirsty savages' can apply to any alignment depending on your perspective.
Lawful Good Paladin can easily find themselves fighting evil with 'bloodthirsty savagery.'
A Chaotic Good barbarian who values individual valour and strength, lives by his word, and helps people where he can could also be a 'bloodthirsty savage' when he fights.
The Neutral Good Ranger hunting and destroying their favoured enemy (the power of racism, folks) with bloodthirsty savagery is simply being a Ranger.
Those are all good-aligned examples. Adding extra adjectives does not a moral compass make. The two are not mutually exclusive, and ideally you layer each with the other.
As a final point, in my experience (35 years of RPGs next week, damn I'm feeling old now), when I join a game and the DM says they don't use alignments because <insert reason here> it's a big red flag to me that I won't (personally, at least) enjoy the game. Primarily this is because usually the DM in question has historically handled all NPC interactions off the cuff without putting consideration into differing points of view. Every NPC invariably becomes an extension of the DM's own personal values. There is no nuance to morality. And they have naturally believed the opposite - that they are in fact worldly enough to understand many varied perspectives. *sigh. Such never turns out to be the case.
As DM I know full well my own bias will get in the way of interpreting such things, and as such the alignment system is an extremely handy filter for getting out of my own head. With a glance you can immediately get a solid grasp of where a character is coming from and build the personality from there.
That's my two copper pieces.