Do we really have to go the route where we argue about whether or not a ficional 48-man raid SOMEHOW comes together with no healers in it? Do you REALLY think that now being a possibility means the GMs just throw up their hands and say "Well, whaddayagunnado? That raid with ten people that can res in it COULD POTENTIALLY have had nobody who could res! A CURSE UPON THESE TIES THAT BIND US TO INACTION!" when someone decides to take out their bad day on Innocent Bystander #27?
For starters - there's a whole lot of daylight between "being in the middle of a boss fight and not being able to res" and "telling someone in advance you're not going to res them because you took their buddy's spot" (which - let's be 100% clear - is a completely made-up accusation that has no mechanical bearing in the way the system is structured. No spot was "stolen," their buddy was too slow).
Secondly - that TYPE of behaviour - refusing to perform your class duties with respect to a particular player - is SPECIFICALLY called out in the ToS as an example of reportable "Aiding the enemy / Uncooperative behavior / Lethargic behavior":
"I don't want to heal because there is a player I don't like in the group."
Not a stretch to have that also apply to giving them a res mid-fight or between bosses, right?
Or how about:
"Using and manipulating enmity-related actions in an effort to incapacitate other players or interfere with gameplay."
...for the aforementioned Tank Buster being deliberately moved into them? That one's under "Obstructing Gameplay Using Combat."
So that's a deliberate tank-buster IN COMBINATION with no res, IN COMBINATION with telling them before the raid that if they don't make room for the poster's friend "we will leave you on the floor" which - it's worth pointing out - uses the word "we," implying it wasn't just one person, but MULTIPLE people, making a team effort to make life hard for the player in question.
Followd by, apparently, jumping on their un-rezzed bodies to get the point across.
Every single one of those things is actionable. They're probably PARTICULARLY actionable in combination.
Do I think every time someone misses a chance to res it's reportin' time? Of course not. Do I think it was done deliberately here, and to the detriment of the player in question? Yeah, absolutely - they TOLD them so.
So, yeah - it's absolutely reportable, and it's absolutely against the ToS.