Pro, all I can say is you must have been reading some revisionists version of history to come to your above conclusion.

Texas had applied for statehood in the US BEFORE the Texas army threw out the Mexican forces within the state and the US govt. basically said until you and Mexico get your shit sorted out, we want no part of Texas as a state.

The Texas army, a rag tag bunch of ranchers, farmers and the like, much less well equipped (and way outnumbered) compared to Santa Annas Mexican army, met and defeated them and achieved independence from Mexico. The US govt. had no part of that battle, nor was there even any form of support from them, so they get no credit for having helped Texas achieve independence from Mexico