Long replies are fine! So of course you cant and shouldn't design around assholes abusing something that is a fruitless task and in the end pointless. In my mind there are 2 types of people who use X card in particular those who are acting in good faith, who are normally more conscious around issues and people, and those who are preformative about the whole idea.
People who are preformative are the people who would abuse this tool, and in my experience there are a lot of them in the community. Im really happy to hear that you have positive experiences with using X card but the majority of people who I have talked to about this only ever have negative feelings towards the use of the card. The major problem with the X card is that people use and then go "Right no need to address underling problems or talk in depth with the group I have in front of me I can just tap a sign" and I know people on this forum are in the know on how its important to be communicative with players and the value of trust. The vast majority of people who use X card don't think past the "rule". Where I believe the harmful part, come in is where people will just look at safety tools and go "Yep we are okay now we have this piece of paper".
I would also like to see more tools created by marginalised people, a lot of what i have across have been written by Cis white non disabled men and while I'm sure they are trying their very best to be good allies it just shows very clearly to me there are gaps in the knowledge and or experience.
Im really bad a TLDRS so sorry for the read!