I’m pretty sure McDonald’s Cyrus isn’t a bot.

No big company would let a bot solely do their social media. Waaaay too much potential to cause a PR disaster. They'll use bots to do stuff like search for posts, schedule posts, and come up templates, but a human would definitely be involved in some point of every single post.

This is probably some human who is told to basically spend all day searching for people referencing McDonalds and replying to their comment based on their tone. They probably do it so much that they were half in autopilot and didn't notice who posted it or how it looked so obviously like an ad.