Isn't this how it started 80 years ago in Germany?

[leveymg]

22. If the sign were surrounded by firearms, it might. That is exactly the case here.

I don't know what the personal history of the shop owner is, but if he could be shown to have been involved personally or as part of a group in hate crimes or violence against Muslims, I would say, this might be an act of intimidation that could be actionable.

I believe that this is a case of display with the intent to intimidate a specific group where, like a noose or burning cross, the court has upheld bans of some symbolic acts amounting to "hate crime" as constitutional: http://www.firstamendmentcenter.org/states-move-to-add-nooses-to-list-of-outlawed-symbols

Constitutionality of noose-display laws

Opponents of such measures question the wisdom of targeting a particular symbol. They point out that the U.S. Supreme Court twice, first in 1989 and again in 1990, struck down state and federal laws singling out flag-burning. They worry that the list of disfavored symbols could grow and lead to a reduction in freedom of expression.

Supporters of noose-display laws rely heavily on the U.S. Supreme Court’s 2002 decision in Virginia v. Black, which upheld the bulk of a state cross-burning law. The Virginia law provided: “It shall be unlawful for any person or persons, with the intent of intimidating any person or group of persons, to burn, or cause to be burned, a cross on the property of another, a highway or other public place.”

The high court reasoned the cross-burnings done with the intent to intimidate others constitute true threats unprotected by the First Amendment. Justice Sandra Day O’Connor wrote in her opinion that “when a cross burning is directed at a particular person not affiliated with the Klan, the burning cross often serves as a message of intimidation, designed to inspire in the victim a fear of bodily harm.” She continued: “Intimidation in the constitutionally proscribable sense of the word is a type of true threat, where a speaker directs a threat to a person or group of persons with the intent of placing the victim in fear of bodily harm or death.”

The Virginia v. Black opinion explains why many of the noose-display laws, rather than imposing a flat ban, contain language requiring that the display or drawing involve an “intent to intimidate.” The Supreme Court reasoned that not all cross-burnings necessarily were done with an intent to intimidate and, thus, may not qualify as true threats. The same logic applies to noose displays.