I don't think this is true, or certainly not unarguably true. You probably win against Paxton because disgusted Republicans stay home (true swing voters are weird and you do not appeal to them like this) and you inspire Democrats to go vote.
But even if we accept that it is true, wearing a big T-Shirt that says "I am trying to appeal to Republican voters" does not actually appeal to Republican voters!
This is how you get on TV and you get big donors to give you money. This is how Lis Smith continues her career. It is not how candidates that she supports win. Ask Mallory McMorrow, who flamed out after going the full Lis.
Lis doesn't win elections. She wins her salaries.
You can argue to yourselves that the big donors and PACs that push candidates are actually not the candidates' campaigns, but sometimes they essentially are. All on the same page.
