Q: Why do people not play healers?
A: because of people like SeraviEdalborez
Just kidding

Excellent healers know how to DPS and heal - which is basically what Seravi is talking about.
You'll have to constantly push yourselves to improve if you want to get there.

However, I feel that it is unfair for people to expect all healers to be able to do both?
My stance is that a healers job is to heal. But if you can heal and DPS, that's an added bonus to the group.
Perhaps I have lower expectations of my pug healers?