To get this out of the way: DPS tools are part of a healers kit and I firmly believe that getting the most out of your entire kit the biggest difference between a Novice and a Veteran. That said...

Everyone has basics of their kit that shines better than other roles, though not necessarily better than others within their role. Tanks mitigate dmg and control enmiity better than all other roles, healers restore hp of the party than all other roles and DPS deal enemy damage better than all other roles. Those are the basics and while jobs dip into other areas with dmg, healing or mitigation it is not a real substitute for the role intended for it.

If everyone is healthy, by all means DPS. Please. It's part of your kit and I'd love to see your kit put to use. And at the same time, heal people who need healing and raise people when they die.

I've seen healers straight up refuse to raise people for several minutes and instead broil/glare/malefic spam. I've personally died to only raidwide dmg and stacking mechanics because the healers flat out refused to ever cast a healing spell my way - a single aoe healing didn't even happen.

I'm not in the "healers shouldn't DPS" camp. You should, it's part of your kit! But at the same time, it should never be a higher priority than the basics of the role. If someone dies that could've been saved from your healing but you were too busy DPSing that's where I take issue. Even if it takes away a precious GCD from you.

I'm not going to fault you for deaths outside of your control - you can't heal stupid and I'm not expecting you to. But the deaths that are in your control are. Not raising a dead DPS out of spite just because they died at no fault of their own doesn't do anything other than show incompetent you are at the role.