Copy-paste reply bots are clearly "bots" IMO - but these seem to be falling out of favor because pointing out many identical replies tends to be a very effective "dunk" on the idea they are promoting.
Someone found screenshots Sally Albright's tooling in a support request: she had ~50-100 different accounts with unique identities. She could post replies to a given tweet from multiple different accounts from a single page. However, liking and retweeting each others replies could be fully automated (with some randomization of timing and which accounts are used).
Albright has claimed that the accounts she managed were originally owned by people who gave her control of them. I am incredulous, particularly because some accounts were identified as using a dead person's image with a different name. But there is the possibility that she was given the impression by whoever provided these accounts to her that these were 'real' accounts where the owners consented to have them used in this manner.
It gives the capability for a single person to seem like they are a crowd of like minded people all in agreement on social media. I believe this model of automated likes/retweets but manual replies is the most common (and pernicious) method used today - practically impossible to prove without data outside the platform it is occurring.