@Espiritus_Corvus There are two main mistakes in your reply. The first is your claim that Sikhs arrogantly attempt to impose their culture on others and are not willing to accommodate the ambient culture. As I have already noted multiple times, this is simply false. The traditional kirpan was a fully functional weapon that was worn but not used. In order to comply with modern worries about weaponry, however, Sikhs have modified their kirpans in various ways (such as dulling the blade, reducing the size, and bolting the sword into its sheath).
As such, it very frequently is reduced to something very much like a piece of jewelry (often small enough to fit in one’s pocket). And as no religious rule prevents a Sikh from temporarily handing over a kirpan for inspection so that one can confirm that it is dull and bolted, your worry about being unable to determine the difference between a kirpan and a weapon that might be used for violence is unwarranted.
Furthermore, these compromises have largely been the result of bilateral discussions between Sikh leaders and government officials. Sikhs are quite possibly the most accommodating religious group in the US. They are certainly more accommodating than Christians (who like to pretend that they are the culture).
Note that I am excluding for the sake of this comparison groups whose beliefs do not come into conflict with US laws. As there is no conflict, there are no grounds for calling such groups accommodating or unaccommodating, and thus no grounds for calling them more or less accommodating.
Second, you have continued in your mistaken insistence that this is a conflict of cultures. As I have already pointed out, it is not. It is the United States’ own laws and culture that puts a high premium on religious freedom, and thus it is the United States’ own laws and culture that should—if consistently applied—grant Sikhs the right to carry their kirpans so long as they are willing to make accommodations for safety concerns (which, as I have already noted several times, they do).
Note also that your freedom of speech comparison doesn’t actually pass muster. The clear and present danger standard was found unconstitutional and replaced by the incitement of imminent lawless action standard. In other words, speech must be far more than vaguely unsafe to warrant restricting it. So while Sikhs should—and do—expect to be questioned regarding the kirpan, that does not mean that perfectly safe kirpans should be seized or the people carrying them refused entry to theaters.
Careful readers will have already noted that I explicitly refrained from giving my support to the Sikhs in this particular case, as they do not seem to have done their part to accommodate safety concerns. In this respect, I completely agree with @thorninmud‘s point about renunciation. If they refuse to make any compromises, then they will have to adjust their behaviors accordingly. The blanket ban suggested by @Ron_C also strikes me as unwarranted, however, thus the moderate position I have taken.