How would an optional, official parser be toxic?

[Penthea]

No one is suggesting that a parser is the only way to see if someone is playing correctly

You'll find that in the below quote from your previous post you did exactly that. Perhaps this isn't what you meant, but this is how it appears.

If you're a pld at o11s, your only combo should not be just the halone combo and spamming shield lob. Nor should you be spamming cure 1 142 times at The Burn as a whm. The only reason why we even know they did this is because of the parser.

I don't see how you're going to catch all that while fighting anything in savage as well as how much dps each player did.

No of course you will not catch every single thing, especially in savage as sometimes your attention is demanded so much that you can't keep watching every combat detail that is presented to you. I even said parsers make it easier to access this information. I was merely correcting you when you said the only reason people know that someone did something wrong is because they could see it in a parser, and I was stating examples of how you can see poor performance without one.

but its an easy solution to get players to understand what they're doing wrong from the start without taking any risks or wasting time, because in the end, most people don't want to teach a player how to play their class during savage and would rather just kick and replace them.

I completely agree that parsers are an easy solution to get more indepth combat information. While a lot can be spotted from personal observational skills and experience, a lot of what players do wrong is sometimes too subtle to see in the heat of battle or you simply haven't the time to look. But this doesn't change that you can spot quite a lot on your own. Very often if someone is really bad at the game it will be obvious without a parser.