Not sure if you are serious or not here. From your inability to understand how damage in can be helpful, something extremely obvious, I would say you are intentionally misunderstanding it.
Do I need to restate the obvious for my argument for parser, it's pros are extremely obvious, thought from the last bit of your quote, (that objectively wrong fear mongering bit.) you seem to have an emotional bias against them, for reasons one can only guess at.
Also, has the game been "Doing just fine for years"? Has it really? Maybe for you, but what about all those groups that constantly fail DPS checks, look at BEX for an example, or in the "years" category, Amadapor Bees nerf.
Yes, obviously I am the exact kind of elitist scum you want me to be, after all, I support parsers, I spew venom everywhere ( though your words do seem to have the tone of what you are projecting on others, similar to others who have taken up your pitchforks and axes).
Also, all of the info in the parser is already recorded by the game, just in an impossible to follow chat log box, so as far as your resource argument... mongering, mongering, mongering.
Of course it can't play the game for you, that's essentially what it would be doing if it did what you suggest here. And of course it can be abused, everything in the game can be abused to that end. Hell, emotes can, do you aggree with that insano who was here talking about sicing the child protective services on SE because emotes can be abused?
Also, of course, people new to parsers won't be experts, like all tools, you have to get used to them to be proficient with them. However, they are fairly easy to understand at a basic level, and just as information can be used to berate, it can also be used to defend, and surprisingly enough, to improve.
Seriously though, why would you even bring up that it doesn't tell you what buffs and debuffs to use optimally, of course it wouldn't sit there and go "Virus now!" , "eye for an eye now!" but, with the info from it, you can figure out what are the better times to use these.