I work in Texas and this is definitely a real thing. In person and within the company, sometimes swearing happens. It would certainly get you in trouble if it happened a lot on customer calls though. We may not care personally about it, but who knows what your customers opinion on it is, so it is better to be polite. It is also very easy to just try not to swear unless you are one of those people that has been swearing like a sailor in every sentence your entire life, which would probably be interpreted as you having some kind of self control problem.

I should also mention that this attitude is not just a liberal vs conservative thing. I've lived in Austin and Houston and Dallas (all three are about as liberal as any other major city in the country) and swearing in a formal setting is frowned upon in all three.