Firstly, I think people who don't raid Savage or Ultimate should take a seat. You do not know how those fights work. You do not know how Cactbot works. You are just pearl clutching.
I don't think people who use Cactbot are necessarily cheating, but I do think the crutch makes them worse players. If you're in a PF group for Savage and something goes sideways, you can tell who doesn't really know the fight as well as they should at that stage of prog based on whether or not they're adjusting for other players' mistakes to save the run. I also think it's a bit of a gray area with calling mechanics earlier than you can see them. The reason I think it's a gray area is because players with low ping literally see tells and mechanics before players with high ping do, and they also have more time to adjust their position; I didn't actually realize this until I raided with someone doing callouts who had much better ping than mine, because he was making the calls for E11S safe colors before the animations even started on my screen, and he does not use any third party callout tools. Does that mean that Cactbot is an equalizer between low and high ping players? I saw someone say that before COVID prompted working from home, the game was tested on 0ms delay. Assuming that's true, the fights weren't designed for the absurdly short reaction times Brazilian players are given, especially in Ultimate fights. You cannot talk about fairness in reading mechanics in faster paced high level fights without talking about ping advantage, particularly in cases of dramatic differences in latency.
I think there is also a disrespect for other players' preferences going on here. Some people, like myself, value figuring the fight out like a puzzle and learning the mechanics organically. Other people value their execution of the fight first and foremost. They don't care about figuring out what the mechanics do and how. They care about handling the mechanics optimally and pushing their performance to the limit. It's unfair and unproductive to police other people for getting different things out of a game than you do. If you're not in a party with the people using Cactbot, why does it matter? If you're paranoid about other people in your party using Cactbot, put together a group of people who you know aren't using it to clear with you. It isn't that deep.
As Sotaris has patiently explained multiple times, Cactbot is not a magical, psychic force that knows what every mechanic is automatically with no help, and it has no bearing on competitive world first prog. Players develop timelines and figure out how to programmatically read mechanics from the client, and THEN the callouts are worked into Cactbot.