I have a prejudice against WHMs now almost as big as some people have against mentors.
The thing is, you don't know if other healer wants to soloheal or if they just don't trust you to do your job. People not putting a slightest effort in assuring others they don't need to work they axes off for the group not to die is one of the reasons for this. The amount of "oh god, it's another one of these days of me solohealing, isn't it?" and "great, I'm gonna live on 5% all the time, ain't I?" is high. I saw enough entitled so called "healers" leaving tanks to die and then complaining about them not popping DCDs, despite tanks performing perfectly, I just don't trust White Mages I don't personally know anymore. I stopped allowing WHMs joining my PF groups cuz of all the Glaremages spamming 1 button with Assize on some special completely random occasion when other healers forced to use everything in their kit to prevent people from wipes on healchecks. Yes, that bad.