You didn't read enough b You apparently don't see the part where it talks about SFA and his 300 families. I guess you don't get that it was after Texians outnumbered mexicans that it was made illegal to come to Mexico. They were allowed to be there. You should read more books about it other than a Wikipedia article.
I'm from Texas and own many books on the subject.
They did outnumber them, they were allowed to be there. They revolted because the Mexican government wanted them to pay taxes and outlawed slavery. Around this same time, they stopped immigration. It continued illegally for years before they rebelled. Many of the people who fought in the revolt were American 'adventurers'. Basically, they were just there to fight. Texas joined the USA for protection from Mexico. Then the USA took half of Texas and turned it into other states. Also, please note that we won Texas from Mexico when we invaded them and beat their asses. It would be like the CSA joining France and then France invading the USA because they invaded France for being in Georgia or something. Call it what you want, but we land grabbed Texas.