Why do Texans and Texas politicians seem to be adamantly opposed to an increasing federal role in state matters?

The majority of Texans and Texas politicians tend to be conservative (the American meaning of the world), and this means that they support economic liberalism, free markets, state's rights, and they oppose big government.

These views are incorporated in the modern political view of the Republican Party. This is why Texas is a state where the Republican Party holds more power than the Democratic Party.