Close, no cigar:
what it's about is whether or not your employer, the "guy who owns the parking lot," has the right to deprive you of your Constitutional rights on the way to and from work
Now if you hate guns, fears guns, or think guns are somehow inherently evil, just say so, but don't try to confuse a rational discussion.
The employer is doing no such thing. He's making a rule about parking. Plan to follow it? You can park. Plan to break it? OK, you can't park. Park somewhere else. It's his property. You may not like how he uses his property. It might be inconvenient for you. But I'm afraid it's his, not yours.
Now if you hate guns, fears guns, or think guns are somehow inherently evil, just say so...
If you're going to resort to ad homina, you'll have to do considerably better than that. I'm not only pro-second-amendment, but also a hunter. I have nothing against guns. Rather, you have something against property rights. You think that someone else has to follow your rules on his land. Can't agree with you there, comrade.