You don’t have to say anything like it, no replacement needed.
The phrases like “black lives matter” and “trans women are women” imply their opposite. That is, the only reason they are being said is because they aren’t true. They are said in an attempt to make them true.
When people hold a sign saying black lives matter they aren’t celebrating the great respect that is given to black people. They are protesting that black lives do not in fact matter to some people. They are trying to make it so that black lives matter.
I think the downside of this approach is that it creates a kind of backlash when you make a kind of generalization about a lot of people saying they care less about black lives than other lives. Whether it is true or not, they will feel falsely accused and become defensive, dig in, and look for reasons why they are actually fine.
Similarly with proclaiming that “trans women are women”. It points the finger at anyone who disagrees, saying they are wrong about women. Maybe they grew up with an idea of what the word women means. Now you are telling them they have been using the word incorrectly for a long time, maybe decades. You might even accuse them of transphobia or bigotry based on a disagreement over semantics. If they feel this is unfair they will not be won over to your cause.
You might say indignantly “what how can you say the it is not true that trans women are women?”. Well, let’s think for a minute about what it takes for that statement to be true. For that statement to be true, it would have to be the case that most of the time you see, hear, or read the word “women” it refers to cis and trans women using the recent idea of self-identification of gender rather than the prior one.
If we had reached that point, then the statement would be true, but also it would be totally uninteresting to make the statement. It would be like saying “women are also human” or something (hopefully) uncontroversial.
As for how to get there, I’m not sure.
Maybe more inclusive language like “get to know a trans person before you judge” would push people to take a step that is known to reduce transphobia. Or “treat trans women with dignity” as a way to evoke a person’s gentler nature? Or “if she looks like a woman and talks like a woman, don’t be rude, treat her like a woman”? Kind of random ideas there, though.
I don’t know the right answer, but the nasty rhetoric and accusations people glibly throw around online to degrade and vilify people who aren’t happily jumping on board the trans movement train…I personally think it’s divisive and unproductive. It’s going to lose potential allies rather than recruit them.
I feel like you’re making some assumptions here about what I’m “advocating” for. You don’t know me and I don’t think it helps your cause to think you know people well that you actually don’t know at all.