So why do you think there were two versions, one pro and the other anti?
There weren't! :)

There are multiple renditions ("versions," if you like?) on record. (Most if not all of these, that I believe anyone is aware of, appear in the "Advent and Development of Chanties" thread. One can open the thread and do a search / Command-F on "SANTIANA" to locate them.)

Some renditions say "Santa Anna won/gained the day", some others say "Santa Anna ran away", and yet others say other things. The quasi-real events in all these renditions do not match up. They talk about battles of Monterrey (1846), and Molino del Rey (1847) -- two different battles, the former in which the U.S. was victorious, the latter in which the U.S. basically lost. And IIRC, Taylor and Santa Anna were not directly involved in either battle (but rather overseeing the whole conflict). Then there is the battle of Buena Vista, in which the two *were* engaged. Hugill incorrectly mashes up all three of these battles as if they were the same.

My point is that there is a lot of "stuff" there, some clearly inspired by current events, other surely mixed up after the fact by chantymen. These don't cohere into two coherent versions. That would be a construct of later collectors (most notably, Hugill) and, I guess, later 20th c. singers.

I find it rather frustrating to have to de-construct the narratives of recent presenters of songs like this before discussing their origins. It is much easier just to start from scratch with no theories in mind. Otherwise it's like trying to re-coil a rope that someone has tied in knots.