I have seen this being done before and was *almost* caught out by one. The doofus attempted to do the same thing (he was uninviting people) so we stopped dps-ing, the bunny slaughtered him and we reformed a raid without him.
Technically, regardless of assists, I believe only the Raid Leader has the capacity to 'uninvite' or disband a raid. I am happy to be corrected however.
Lodge a ticket/complaint. At the very least, he should have said bunny removed from him.
Do not join CRZ pugs for this - stick with your own realm (even if it's more painful).
If you get into a raid and it's set to Master Loot, ask for it to be changed. If they refuse, make it known and bail.
Add those people to ignore so, at the very least, you'll never have to be hit by their scumminess again.
This is a classic reason, amongst many, as to why Darkmoon Island should never have been CRZ'd.
In the end, I got so sick of these raids, I bought my bunny. Yes, the loss of gold was painful. But not having the stress of these kinds of events has been a relief.