@Gargron Much respect for considering this!
As a long time consumer of online communities, my sense it that the real danger with Quote Posts isn't harrasment (which can happen plenty of other ways), but they help basic misunderstandings to accelerate into angry conflict.
Giving the user the choice should greatly address that concern w/people who don't want that drama. The worst dog pile I was under came via friendly accounts after one person amplified one misunderstood one post in a thread.