I'd say this refers to the "new" generation of healers, they have to be told to use dispel, they don't do it by reflex. Also they rather be spamming stone2 than dispelling slow from an actual dps cause they are the whm or sch OP dps.
I'll also add, some first judge if it really is necessary to dispel something, like pacification, which only lasts 5 seconds, or of it really affects the path of the battle.
I never waited to be told to remove something. Normally if I see a new icon I try to dispel it, I learned that way petri could not be dispelled, same as Melt's paralyze just to name some. I get mad when I enter ST and at Amon healers just stand around while ppl are dying of thunder dot or bomb. I tell them in party that these debuffs can and should be dispelled and they go "oh I didn't know" or "meh the bomb only lasts a few seconds" /wristshake. Or in WoD when they rather be spamming cure than dispelling thunder/poison on Cerberus.
I've seen excuses for not using esuna/leeches, and I'm sure you will get many in this thread. I personally can't understand any of them, whatever the reason, there is no excuse to not dispel. Unless of course as you mentioned, someone is dying. Even on speed pulls when the tank gets paralyzed or poisoned, I can sneak in an esuna, many healers wont and will say it's not worth it.
I'd rather have a healer that stoneskins, esunas, and puts the party's health first, than the one that starts in cleric stance and doesn't give a damn about debuffs as long as he/she is not directly affected by them, since he/she is the great dps contributer to the party.
Oh and yes I totally agree!!! This damned berserk macro!!! I also try to make a point by NOT dispelling the debuff, see if the tank gets it. We really really don't have to be told! And if we do, hehe then you got the guy that doesn't give a damn anyways and won't do it.