Why should a Texas-specific event be recognized nationally? As mentioned upthread, there are more comprehensive dates with which to recognize the end of slavery.
It’s not Texas-specific. It’s the date upon which it became officially recognized by all America that slaves had been emancipated. It’s a significant date in history. And it should be federally recognized.
If Trump made that happen, can you imagine how that would affect his reputation among African Americans ... for decades if not centuries?