You can still verify the result of an automatic merge. It's simpler to mark a suggestion "y" than to resolve conflicts that could be solved automatically by hand.
So I don't think this reasoning holds any ground whatsoever.
What they're actually objecting to of the idea of not having a human in the loop. I suspect if you pitched these smart merge algorithms from the "click to accept auto merge" angle, they wouldn't have much of a problem. Instead they seem to be pushed as a way of avoiding interaction.
Nah, I'm not sure the comma is grammatical, might actually make the last part a contradicting enumeration. The blame is on me, I quoted out of context and was a bit on the slow side understanding. The sentence is just not written well, too.
On topic however, missing one such conflict is easier, if you have to spot it after the damage is done, instead of having to think about it yourself beforehand, no?
So I don't think this reasoning holds any ground whatsoever.