I appreciate that your Yankee, Cowboy, and Laker fanships are all real and heartfelt.
Most Astros fans are from Texas or from Houston specifically. How does one "bandwagon" their home city's team? Interest wanes in down years and increases in winning years, but fans are always fans.
I go to more Yankees games per year than you've been to in your life, and I've been to more Mets games than I have been to Astros and Yankee games combined. But all that means is that I'm an adult that likes to watch baseball and can afford to go to games. It doesn't make me a true fan of either one even if I'm coming around to the Mets being my second favorite team. As a poor kid in Houston, I went to games when I was lucky enough to get tickets, but otherwise watched nearly every single game on TV. That made me a fan. But really, I'm a fan of all Houston teams. Watched plenty of Hotshots and Comets games too. The fact is that you chose the big hated name because you wanted to be different or a dick to your friends who were fans of Texas teams. If you grew up in the Bronx, you'd probably be a Red Sox fan for the same reason.