Ah, got it.
Yes, some people do seem opposed to some of the mechanics.
However, my opposition is specifically because of the fluff. I'm ok with "you are healed because...well, it's magic". What I'm not ok with is "you are healed because your character find's somebody else's character to be inspiring". The latter is telling me what my character thinks.
So mechanics that I'm willing to accept from an Avatar or a Cleric or a Bard are not necessarily mechanics I'm willing to accept from a character whose fluff is "other people look up to your natural leadership and general all-around awesomeness".
A common response to that is, "It's just fluff...ignore it." But then when I say, "Well, the Cleric and the Bard also have fluff...why can't you ignore that?" all of the sudden the fluff becomes really important. I'm not saying my position conclusively demonstrates that the Warlord shouldn't exist, just that the validity of my position is equal to the validity of the pro-Warlord position.
And the Dispel Magic argument is just a distraction. Sure, that's a real mechanical effect, but it's an edge case. Almost all of the abilities I see proposed, and the ones most argued about, wouldn't be subject to Dispel Magic anyway. (And if there were an exception, and immunity to Dispel Magic really made that much of a difference, I would posit that that only demonstrates the need to make sure it's somehow dispellable.)
I can certainly agree that I don't want my character being told "You are inspired" without some possibility of magic (like the bard) being involved. However, I also don't see my own opinion as a reason to not let others have what they want. If a warlord comes up, and is loaded to the brim with mechanical effects that tell me how I feel, I will just ignore it. If someone decided to play it in the same game as me, my reaction would depend on my character. It would probably be in one of three broad categories.
1) My character is a nice person, and does not want the Warlord to feel bad, and so forces themselves to act "inspired", thus pushing themselves beyond previous limits (mechanically, they gain some health through force of their own need to keep people happy).
2) They get stronger through spite. classic "I'm doing it, but NOT because YOU told me to. Just because I FEEL like it!".
3) My character actually has a reason to feel inspired by the Warlord character (probably a rare occurrence, where I specifically build my character to look up to someone elses.)