I'm going to do my best not to appear rude here, but I think your moral/emotional arguement is being pushed up agains ForsakenRoe's Logical arguement. Its not a "meta" requirement, they're referencing, its a DPS-CHECK requirement.
The DPS Checks in this game are mostly lenient where, yes, a Healer could succeeed without doing DPS - but at the Savage level (on Content & no echo) and at the Ultimate Level (at any time), you can't meet the DPS check before Enrage if Healers are just healing. They are correct in that it is mathmatically impossible to achieve without each member of the group contributing damage - including healers. You can call it cheating to know that it is mathmaticallly impossible (or close to it, depending on the case), but that is generally well-accepted knowledge by the average player who actively participates in the raiding content this game offers - even those who swear off of all add-ons.
Your lack of experience in the game is why you are championing the cause of Healers only need to heal. The Developers shifted the DPS requirements of content to require support players to also focus on damage back prior to Heavensward (Time line might be a little wrong, its been 10 years so cut me some slack), because of Player Demand - and it has been that way ever since. This bred the well known meme, healers are Green DPS. Tanks are Blue DPS.
Lets not get uppity and big-ego'd because we disagree emotionally with something. Base your rebuttals on something more substantial than "This is my belief" for a more constructive and objective-based discussion.
Othewise, you're just shouting into the void for no discernable reason other than to be upset with other people... and that's just obnoxious I'm sure you agree! I've done it plenty of times. I'm a very obnoxious person.
Anyway, o7