I would respect these kind of virtual signaling messages if they provided any kind of balance. Maybe a throw away line like "whether you are in DC, or violently attempting to burn down the federal courthouse in Portland".
"Virtue signaling" is usually meant as an insult, implying that they either don't really believe what they are saying or wouldn't be saying it if they thought it wouldn't be a net benefit to business. I don't get any hint of either of those. Are you sure you're not just using the phrase for its negative connotation, because you don't like what they're saying?
That is exactly how I mean "virtue signaling". If they had a few people looking to use their services, which they hold themselves out to the public to offer, and they didn't want to, then they could just say no. To post a public message about it is just a way to say "look at me world! I am a good person, doing the things that will make people like me". Some people wear burkas to show their allegiance to a way of thinking, some people post things like this. It is all a way to showing fealty.
This isn't mere virtue signaling. If I owned a bar and it started attracting a racist, violent crowd, after having to kick a bunch out by force, I'd start putting up loud signals I don't want their business.