You won't find pro-immigration, abortion rights or even gun control topics displayed openly in workplaces (in most cases).
While conservatism isn't much about sensitivity, today's conservatives are quite sensitive and intolerant to progressive policies (wherever they may encounter it). While I am not strongly positioned either way, I find it quite sad that the Right has to simply deny even the very science of global warming despite the handwriting on the wall being what it is. This intolerance and sensitivity is often the root of their desire to be heard, and loudly. As a result, they don't mind being particularly expressive and indignant about 'proclaiming' their beliefs, which can includes posts on internal forums.
If you're (actually) fired for your beliefs and you're able to prove it, then you're more than welcome to access the various tort statutory laws that Liberals have provided you (by the way) and sue for 'wrongful termination'.
What shocks me about conservatives is how they don't see the hypocrisy of demanding the same 'tolerance' from liberals when it is intolerance that underlies the majority of their own beliefs. Conservatives claim the very bedrocks of civilization regardless of country: the military & patriotism, religion, and business. Yet, they spend these resources only for their own political advantage instead of that of the country as a whole. Witness tax cuts for the rich.