You're right man, it's a double standard, but it's something we've gotta deal with. I wouldn't call it discrimination, just company policy. You've also gotta consider the companies pov, they deny someone some religious right, the fuckin' planet explodes with rage! Best to just avoid that and let rasta man wear his dreads..
If I were you, I'd have a shit load of fun with this, they say no "hats" right? lmao, get the funniest fuckin wig you can find, I'm talkin Joe Dirt mullet, that guy from High School High with the racecar course on his head lmfao, go NUTS! What are they gonna say then? "No... fake hair either!"
Or just pretend to be beginner rasta yourself lol, how can they prove you're not? pwned.