If your goal is to create a space where people can only say nice things and only agree with you, then yeah this a great method to do it. It's a great way to create a tiny bubble of like-minded people and allow you to spiral ever deeper into the bubble as outside debate and challenging of assumptions becomes disallowed.
"Harassment" and "disagreement" are two separate things, and the fact that you're conflating them here tells me you're not a member of a marginalized group
I don't think it's especially polite to assume someone's degree of marginalization, marginalized people can also disagree on what moderation tools are desirable
This tool cannot prevent harassment and allow disagreement. The author can unilaterally choose what to remove, no matter the reason. When you give someone this capability, you will remove discourse and guarantee echo chambers.
TBH I think part of this is for very large accounts, where there is literally just too much engagement to deal with. You kind of need to be able to filter and create your echo chamber to preserve your sanity and use the application the way it is intended to be used (not some kind of updates-only account). Personally I highly doubt I will ever have a problem where I either need to get engaged by with someone (seems unhinged) or need to click extra buttons to disengage from someone unless I'm being pushed to do so by e.g. an excessively rude person or someone who is behaving unhinged at me.
Like these are low stakes. If someone wants to hide polite disagreement, that's cool, they're managing what it means to be their follower and if I don't like it I can stop following them. It has nothing to do with me personally and they're not obligated to receive disagreement because I want them to, that's a weird position to take.
