@Gargron I've written this elsewhere, but I suspect with correct moderation tools, we could solve the pile-on problem whilst still having quote toots.

E.g., if a quote toot, allow reporting for misuse / abuse, and then provide a means to disable quoting for a user for a time period / indefinitely, and only allow quoting of public content

Additionally, education can help change the message here: act bad & you loose the privilege. Potentially even "disable quotes" as a setting.