It's useful, especially for people who aren't already steeped in cultural norms, to have a reference for "how might I come across if I say this". Words simultaneously communicate meaning and connotation, and it's helpful to understand both the meaning and the connotation. People aren't going to misunderstand the author of a text that says "blacklist"; they're going to understand just fine, perhaps including ways that the author would prefer not to have been perceived, or perhaps in ways the author intends to be perceived.
Tooling like this won't change the minds of people who are determined to be offensive (with or without the added assertions that they don't think it should be considered offensive). The point is to inform people how they may come across. It would be incorrect to say "this word is universally considered offensive", just as it would be incorrect to not label the word at all; it'd be more correct to say "this word's status is [disputed/transitional], with [an increased trend towards being considered non-inclusive], and consequent [doubling down by conservative language users]; consider avoiding due to any or all of offense, controversy, or politics".
Until just two years ago, "whitelist/blacklist" was completely normal language with no racial connotations, and I would wager that it's still viewed as completely normal by the vast majority of people. However, in just the last two years, people of a certain political persuasion in the US have decided to make these phrases into an issue.
If it is critical for you to communicate and come off well to a relatively small subsection of upper-middle-class liberal Americans, then these suggestions might be helpful. If it is critical for you to communicate with fundamentalist Evangelical christians, then a different set of suggestions might be helpful. I view the two situations in exactly the same way. However, if you're just writing for a generic audience, then these suggestions come across as unwelcome proselytizing.
"Ain't" is a perfectly normal construction in some dialects of English, but if you use it in a formal setting, people will notice and will think it's strange.
It could be useful for a product like Google Docs to tell you not to use dialectal grammar like "ain't." If you're writing a formal document, you probably want to avoid that kind of language. However, if Google Docs goes beyond that and starts telling you to replace completely normal words like "blacklist" with woke alternatives like "blocklist," that feels more like an attempt to establish some sort of religious orthodoxy. It gives the same vibes as if Google Docs were to start trying to push Evangelical religious sensibilities on its users. It's not helpful, unless you think your audience is extremely uptight and you want to avoid upsetting them.