Right leaning people are fired all the time for their views on social issues, and no one seems to have a problem with that normally.
Further if these employees would have been fired to taking a counter view I bet there would have been cheers for their firing
no the outrage here is not really because " people shouldn't have outside-work activities be held against them" no it is more "I agree with these employee opinions and am outraged they were fired for an opinion I share"