That guy was a jerk, Op. Sorry you had that experience, I've had similar in LFR, and back in HLK we had another disc who was like that. I've even run into !@#$%^- Holy priests who insist on shielding tanks. (They, too, did it before the pull so I had to wait for WS or cast a few fast heals to get WS off.)
Don't give up on the idea itself, just get players that are for the team, not for themselves. Boot people with that attitude straight off, during trash, don't let them ruin your raid night.
The haste spirit build thing is ok if you are a 3rd healer just doing atonement on stuff you outgear, but crit=mastery > haste is still better. Ignore his *!@.
If he really did this just because you offered another regular in your raid advice, pfft. I'd get rid of your other regular as well. In our raid we frequently tell players we want a certain glyph/ talent for a fight, and if they don't, hell, booted. We get a replacement if we can, don't raid if we can't, and the whole raid knows who to blame. We even had to boot a hunter who refused to use sporebat (we had no haste buff). EVERY week we had to ask, ask, order, cajole him. One week... he showed up and had released his sporebat. Figured we couldn't make him if he didn't have it. So we halted the raid, and said you have 10 minutes to go tame one, or we cancel the raid and boot you.