Social safety features in tabletop RPGs (such as the X-card) prevent exploration of controversial, sensitive, or extreme subject matter in exactly the same way that safe words in BDSM prevent exploration of kinky sex. That is, they don’t prevent it at all. In both cases the exploration is facilitated by setting parameters inside of which exploration can occur responsibly in a trusting and mutually enjoyable manner. This does not seem all that difficult to grok for me.
Not all tables need the x-card, and there are other ways to implement social safety at your table, but where needed the X-card is a simple and useful tool. Maybe the standing culture at your table is simply not to dive into any subject matter that could be considered sensitive. That’s fine: just recognize that you may not always know or agree with the folks at your table as to what constitutes a sensitive subject. YMMV. Obviously, social safety features should be used in conjunction with and not as a replacement for communicating with the people at your game table.
(Cross-posted from Tumblr.)