You look at the consequence instead of looking at the cause.
All I heard since the beginning of ShB is that healers press a single DPS button over and over again because the encounters are basically not being designed to have you press your GCD heals a lot.
Which means, that, yes, it can feel lobotomized. And that's probably not great design.
But that's not because the healers kit is braindead easy to use. When I look at the healers toolkit, I think it looks pretty solid and far from lobotomized. It is probably just as complex as any tanks or dps toolkits.
However, because the damages taken are not sufficient compared to your heal-heavy toolkit, or because your heals are too powerful, or both, it leads you to spam the same DPS ability over and over again.
And that is the part which is not great.