A lot of shading of Ebenezer's character that I enjoyed. Which I wager ups the likelihood of his death being imminent. How and its impact are up in the air. It will be the second senior council member lost in a short span (as far as wizard life times go), and the Blackstaff at that. The Council will go into upheaval as wizards jockey to fill the power vacuum left behind. This may be the beginning of the end for the White Council as it has existed. Losing McCoy and/or a vote to expel Harry are more than enough to lead to a schism.
McCoy is old and set in his way. He reminds me of my grandfather. He was a product of the life he lived, which is very different from mine. He spouted horribly racist things, but hired a lot of Black people to work for his company at a time that was not the norm. He spouted horribly anti-gay things, but came to love my husband like his own son. McCoy thought he was doing the right thing. To have his judgment questioned by someone else- probably when he's questioning it himself, is sure to ruffle his feathers.
Old prejudices die hard. And McCoy has had multiple lifetimes from a mundane perspective to develop them. Whampires, svartalves... I think McCoy has a human-centric perspective, where Harry is much more willing to take allies and make friends where he can get them. McCoy spent his whole life protecting humans against supernatural threats. I think any supernatural race had plenty of time to cross him and get on his naughty list. Not surprised he has issues with the svartalves. At this point I'd be surprised to hear of anyone McCoy doesn't have issues with.
I also think this showed Harry's growth too. He expressed himself clearly and without devolving to shouting, shooting, or storming off. Sure, the exchange got heated, but there was no actual fire summoned. And ultimately he's right. It's his choice how to raise his child. And as others have pointed out, he destroyed the entire species of the last villain who tried to harm his daughter. He's killed multiple immortals. Only a fool thinks coming at Maggie is a good idea- like Nicodemus, who was goaded to rage by Harry after murdering Deirdre. And look how well that ended for Nicodemus.