You can, but it won’t be adjudicated that way. People can leave or (in a pre-made) remove a player for any reason or no reason at all. The only exception I can think of is trying to remove someone just before the last boss of an M+ dungeon dies (during the last boss fight with % already met), as that can reasonably be construed as griefing (trying to deprive you of a reward despite having participated for 95%+ of the time).
The player may have had a RL emergency or simply doesn’t think this particular comp will time the dungeon and it’s their key. That last bit is the most likely reason that reporting them would be useless… if they left your key (not their own key) then you’d maybe have a case for wasting people’s time, but even then “disband/remove for any reason or no reason at all” pretty much means the staff don’t have to review many complaints about abandoned keys or being removed from a key.
They have started to take note of those that intentionally brick someone else’s key, but action is based on “a great many” offenses of the same nature… a single report isn’t grounds for any kind of action.
You can’t lose M+ Score for abandoning a run (or even completing one WAY over time). You’ll get no automated punitive actions from Blizzard (M+ does not have a 30-min deserter buff; that’s only for queued dungeons, not pre-made groups). What kind of strike are you worried about specifically?