If the "rules" (made by any entity) are so cumbersome that you cannot vigorously exercise your Rights, then those Rights have been illegally infringed upon.
Suppose your company bans guns. Now you can't "keep and bear arms" for 50 hours a week.
Now suppose your state bans open carry. Then you can't "bear" arms at any time, save for those few hours a month you are at a range.
Then trains and planes ban guns. Now you can exercise your Right even less.
So basically, through no action of the federal government, your Rights have been severely violated. What recourse are a Free people to have? Are we simply supposed to move to another state, every time they infringe upon our Rights. Or quit our jobs? Or walk to our destination instead of taking a train?
Do you really think *this* is what our Founders had in mind when they shed blood in defense of Liberty? Do you think when Jefferson, etc.... wrote about Freedom, they had in mind a bunch of bureaucratic needledicks that could make "policy" to effectively eviscerate these Rights?
Quite the contrary, they created a gov't whos primary purpose was to defend our individual Rights. Be it from foreign or domestic enemies.
Unless the government forces all employers to ban firearms(*), you have every right to seek out an employer who won't.
(*) Unfortunately, the courts are trying to do precisely that.