Is DPS'ing as a Healer Vote Kickable?

[Watachy]

Also, I still haven't gotten an answer as to why we queue as tank, or dps, or healer.

Every role provides you a different gameplay like every job. The thing is, casual content (everything out of Savage runs) has been designed in a way you don't need to heal 24/24h and this applies to some Savages turns too.
If you're aren't healing you should be doing something else that ain't slacking around when your party members are trying their best to clear the content for you. Since you've got 3 things to do as a healer: healing, pre-cast incoming damages, dpsing.
If no heal is needed and nothing big is coming, you have to DPS that's all.